add exit

@@ -6,6 +6,8 @@ int main() {
 	string s1;
 	string s1;
 	cout << "Input string: ";
 	cout << "Input string: ";
 	cin >> s1;
 	cin >> s1;
+	if (s1 == "exit")
+		return 0;
 	cout << s1 << endl;
 	cout << s1 << endl;
 	return 0;
 	return 0;
 }
 }
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