#include <iostream>
#include <vector>

using namespace std;

int main(){
  // input
  string S;
  cin >> S;

  string ans="";
  for(auto c: S){
    if(('a' <= c) and (c <= 'z')){
      ans.push_back(toupper(c));
    } else if(('A' <= c) and (c <= 'Z')){
      ans.push_back(tolower(c)); 
    }
  }


  cout << ans << endl;
  // output 
}