#include <bits/stdc++.h>
using namespace std;
int main(){
  string s;
  cin >> s;
  for(int i = 0;i < s.size();i++){
    if(isupper(s[i]))s[i] += 0x20;
    else if(islower(s[i]))s[i] -= 0x20;
  }
  cout << s << endl;
  return 0;
}