#include <bits/stdc++.h>
using namespace std;

int main(){
    string s;
    char *p;
    cin >> s;
    p = &s[0];
    while(*p){
        if (isupper(*p)) *p = tolower(*p);
        else *p = toupper(*p);
        p++;
    }
    cout << s << endl ;
    return 0;
}