#include <iostream>
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]+=32;
    else if(s[i]>='a' && s[i]<='z')s[i]-=32;
  }
  cout << s << endl;
  return 0;
}