diff --git a/suhwan2004/Minimum Add to Make Parentheses Valid.js b/suhwan2004/Minimum Add to Make Parentheses Valid.js
new file mode 100644
index 0000000..ae3d3d3
--- /dev/null
+++ b/suhwan2004/Minimum Add to Make Parentheses Valid.js	
@@ -0,0 +1,28 @@
+/*
+23:53 ~ 24:05
+
+Time : O(N)
+Space :O(1)
+ALGO : for
+DS : x
+Constraints
+- 1 <= s.length <= 1000
+- s[i] 는 무조건 '(', ')' 둘중 하나이다
+Edge Case : x
+*/
+
+var minAddToMakeValid = function(s) {
+    let open = 0;
+    let close = 0; 
+
+    for(let i = 0; i < s.length; i++){
+        const curC = s[i]
+        const isOpen = curC ==='('
+
+        if(!isOpen && open > 0) open--
+        else if(isOpen) open++
+        else close++ 
+    }
+
+    return open + close
+};
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