diff --git a/2202/220207.cpp b/2202/220207.cpp
new file mode 100644
index 0000000..1649b42
--- /dev/null
+++ b/2202/220207.cpp
@@ -0,0 +1,31 @@
+#include <string>
+#include <cassert>
+#include <iostream>
+
+/**
+ * 389. Find the Difference
+ * You are given two strings s and t.
+ * String t is generated by random shuffling string s and then add one more letter at a random position.
+ * Return the letter that was added to t.
+ */
+
+class Solution {
+public:
+	static char findTheDifference(const std::string& s, const std::string& t) {
+		int c[26]{};
+		for (char ch : s) {
+			++c[ch - 'a'];
+		}
+		for (char ch : t) {
+			if (--c[ch - 'a'] < 0)
+				return ch;
+		}
+		assert(false);
+		return 0;
+	}
+};
+
+int main() {
+	std::cout << Solution::findTheDifference("abcd", "abcde");
+	return 0;
+}
diff --git a/2202/CMakeLists.txt b/2202/CMakeLists.txt
index 7a81450..717308c 100644
--- a/2202/CMakeLists.txt
+++ b/2202/CMakeLists.txt
@@ -3,4 +3,4 @@ PROJECT(2202)
 
 SET(CMAKE_CXX_STANDARD 23)
 
-ADD_EXECUTABLE(2202 220207-CN.cpp)
+ADD_EXECUTABLE(2202 220207.cpp)