diff --git a/examples/blocks/block_scanner.py b/examples/blocks/block_scanner.py
index b148c20..ec09296 100644
--- a/examples/blocks/block_scanner.py
+++ b/examples/blocks/block_scanner.py
@@ -1,14 +1,9 @@
 import asyncio
-import datetime
-import logging
-import time
-import typing
 from types import coroutine
 
 from pytoniq_core.tlb.block import ExtBlkRef
 
 from pytoniq.liteclient import LiteClient
-from pytoniq_core.tlb import Block, ValueFlow, ShardAccounts
 from pytoniq_core.tl import BlockIdExt
 
 
@@ -27,14 +22,20 @@ def __init__(self,
         self.shards_storage = {}
         self.blks_queue = asyncio.Queue()
 
-    async def run(self):
+    async def run(self, mc_seqno: int = None):
         if not self.client.inited:
             raise Exception('should init client first')
-        master_blk = self.mc_info_to_tl_blk(await self.client.get_masterchain_info())
-        shards = await self.client.get_all_shards_info(master_blk)
-        for shard in shards:
+
+        if mc_seqno is None:
+            master_blk: BlockIdExt = self.mc_info_to_tl_blk(await self.client.get_masterchain_info())
+        else:
+            master_blk, _ = await self.client.lookup_block(wc=-1, shard=-9223372036854775808, seqno=mc_seqno)
+
+        master_blk_prev, _ = await self.client.lookup_block(wc=-1, shard=-9223372036854775808, seqno=master_blk.seqno - 1)
+
+        shards_prev = await self.client.get_all_shards_info(master_blk_prev)
+        for shard in shards_prev:
             self.shards_storage[self.get_shard_id(shard)] = shard.seqno
-            await self.blks_queue.put(shard)
 
         while True:
             await self.blks_queue.put(master_blk)
@@ -47,23 +48,26 @@ async def run(self):
             while not self.blks_queue.empty():
                 await self.block_handler(self.blks_queue.get_nowait())
 
-            master_blk = self.mc_info_to_tl_blk(
-                await self.client.wait_masterchain_seqno(
-                    seqno=master_blk.seqno + 1, timeout_ms=10000, schema_name='getMasterchainInfo', data={}
-                )
-            )
+            while True:
+                if master_blk.seqno + 1 == self.client.last_mc_block.seqno:
+                    master_blk = self.client.last_mc_block
+                    break
+                elif master_blk.seqno + 1 < self.client.last_mc_block.seqno:
+                    master_blk, _ = await self.client.lookup_block(wc=-1, shard=-9223372036854775808, seqno=master_blk.seqno + 1)
+                    break
+                await asyncio.sleep(0.1)
 
     async def get_not_seen_shards(self, shard: BlockIdExt):
         if self.shards_storage.get(self.get_shard_id(shard)) == shard.seqno:
-            return []
-        result = []
-        await self.blks_queue.put(shard)
+            return
+
         full_blk = await self.client.raw_get_block_header(shard)
         prev_ref = full_blk.info.prev_ref
         if prev_ref.type_ == 'prev_blk_info':  # only one prev block
             prev: ExtBlkRef = prev_ref.prev
+            prev_shard = self.get_parent_shard(shard.shard) if full_blk.info.after_split else shard.shard
             await self.get_not_seen_shards(BlockIdExt(
-                    workchain=shard.workchain, seqno=prev.seqno, shard=shard.shard,
+                    workchain=shard.workchain, seqno=prev.seqno, shard=prev_shard,
                     root_hash=prev.root_hash, file_hash=prev.file_hash
                 )
             )
@@ -71,16 +75,35 @@ async def get_not_seen_shards(self, shard: BlockIdExt):
             prev1: ExtBlkRef = prev_ref.prev1
             prev2: ExtBlkRef = prev_ref.prev2
             await self.get_not_seen_shards(BlockIdExt(
-                    workchain=shard.workchain, seqno=prev1.seqno, shard=shard.shard,
+                    workchain=shard.workchain, seqno=prev1.seqno, shard=self.get_child_shard(shard.shard, left=True),
                     root_hash=prev1.root_hash, file_hash=prev1.file_hash
                 )
             )
             await self.get_not_seen_shards(BlockIdExt(
-                    workchain=shard.workchain, seqno=prev2.seqno, shard=shard.shard,
+                    workchain=shard.workchain, seqno=prev2.seqno, shard=self.get_child_shard(shard.shard, left=False),
                     root_hash=prev2.root_hash, file_hash=prev2.file_hash
                 )
             )
-        return result
+
+        await self.blks_queue.put(shard)
+
+    def get_child_shard(self, shard: int, left: bool) -> int:
+        x = self.lower_bit64(shard) >> 1
+        if left:
+            return self.simulate_overflow(shard - x)
+        return self.simulate_overflow(shard + x)
+
+    def get_parent_shard(self, shard: int) -> int:
+        x = self.lower_bit64(shard)
+        return self.simulate_overflow((shard - x) | (x << 1))
+
+    @staticmethod
+    def simulate_overflow(x) -> int:
+        return (x + 2**63) % 2**64 - 2**63
+
+    @staticmethod
+    def lower_bit64(num: int) -> int:
+        return num & (~num + 1)
 
     @staticmethod
     def mc_info_to_tl_blk(info: dict):
@@ -96,8 +119,9 @@ async def handle_block(block: BlockIdExt):
         return
     print(block)
     transactions = await client.raw_get_block_transactions_ext(block)
-    for transaction in transactions:
-        print(transaction.in_msg)
+    print(f"{len(transactions)=}")
+    # for transaction in transactions:
+    #     print(transaction.in_msg)
 
 
 client = LiteClient.from_mainnet_config(ls_i=14, trust_level=2, timeout=20)