added Description

Author: mauricechouam

Minimum Add to Make Parentheses Valid/code.js

@@ -0,0 +1,15 @@
+/*
+ * @param {string} S
+ * @return {number}
+ */
+var minAddToMakeValid = function(S) {
+    let open = 0, close = 0;
+      
+      for(let c of S) {
+          if(c === '(') open++;
+          else if(!open) close++;
+          else open--;
+      }
+      return open + close;
+  };
+