diff --git a/921. Minimum Add to Make Parentheses Valid b/921. Minimum Add to Make Parentheses Valid
new file mode 100644
index 0000000..7607059
--- /dev/null
+++ b/921. Minimum Add to Make Parentheses Valid	
@@ -0,0 +1,13 @@
+class Solution {
+public:
+    
+    int minAddToMakeValid(string s) {
+        stack<char> stac;
+        for(char c : s)
+        {
+            if(!stac.empty() && stac.top()=='(' && c==')')stac.pop();
+            else stac.push(c);
+        }
+        return stac.size();
+    }
+};