#include <iostream>
using namespace std;

int main() {
    string S;
    cin >> S;
    int i;
    for(i=0; S[i]!='\0'; i++){
        if('A'<=S[i]&&S[i]<='Z'){
            //char tmp = S[i];
            S[i] += 32;
        } else if('a'<=S[i]&&S[i]<='z'){
            S[i] -= 32;
        }
    }
    for(int k=0; k<=i; k++){
        cout << S[k];
    }
    cout << endl;
}