#include <iostream>
#include <string>
using namespace std;

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