#include <vector>
#include <queue>
#include <deque>
#include <stack>
#include <algorithm>
#include <functional>
#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cctype>
#include <string>

using namespace std;

int main() {
  string str;
  cin >> str;
  for (int i = 0; i < str.size(); i++) {
    if ('A' <= str[i] && str[i] <= 'Z') {
      str[i] = 'a'+str[i]-'A';
    }else {
      str[i] = 'A'+str[i]-'a';
    }
  }
  std::cout << str << std::endl;
}