#include <bits/stdc++.h>
#define INF 990000000
//37
using namespace std;

int main() {
string s;
cin>>s;

for(int i=0;i<(int)s.size();i++){
if(isupper(s[i]))s[i]=tolower(s[i]);
else if(islower(s[i]))s[i]=toupper(s[i]);

}

cout <<s<<endl;


}