#include<bits/stdc++.h> using namespace std;//命名空间 分号是英文分号 int main() { char cc; cin >> cc; if (cc >= 'A' && cc <= 'Z') { cc = cc + 32; } else { if (cc >= 'a' && cc <= 'z') { cc = cc - 32; } } cout << cc; return 0; }