restructure zeta/** to storage/zeta/**

storage/zeta/cpp/completed/9086.cpp

@@ -0,0 +1,13 @@
+#include <iostream>
+
+int main() {
+    int N;
+    std::string s;
+    std::cin >> N;
+
+    for (int i = 0; i < N; i++) {
+        std::cin >> s;
+        std::cout << s[0] << s.back() << std::endl;
+    }
+    return 0;
+}