diff --git "a/src/inflearn_coding_test/basic/3-5_\353\254\270\354\236\220\354\227\264\354\225\225\354\266\225.js" "b/src/inflearn_coding_test/basic/3-5_\353\254\270\354\236\220\354\227\264\354\225\225\354\266\225.js"
new file mode 100644
index 0000000..c6a92f1
--- /dev/null
+++ "b/src/inflearn_coding_test/basic/3-5_\353\254\270\354\236\220\354\227\264\354\225\225\354\266\225.js"
@@ -0,0 +1,21 @@
+function solution(str) {
+  let answer = '';
+  let count = 1;
+  str = str + ' '; // 마지막 문자에 대한 처리를 위해 빈 문자 추가 (Sentinel Value)
+
+  for (let i = 0; i < str.length; i++) {
+    const char = str[i];
+    const nextChar = str[i + 1];
+
+    if (char === nextChar) count++;
+    else {
+      answer += char;
+      if (count > 1) answer += String(count);
+      count = 1;
+    }
+  }
+
+  return answer;
+}
+
+console.log(solution('KKHSSSSSSSE')); // K2HS7E