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

int main(){
	char a;
	cin>>a;
	int b=a;
	if(97<=b&&b<=122){
		b-=32;
	}else if(65<=b&&b<=90){
		b+=32;
	}
	a=b;
	cout<<a;
	return 0;
}