#include <bits/stdc++.h>
using namespace std;
int main() {
	char n;
	cin>>n;
	if(int(n)>90){
	    n=n-32;
	    cout<<char(n);
	}else{
		n=n+32;
		cout<<char(n);
	}
}    
/**************************************************************
	Problem: 1971
	User: wangyiyang
	Language: C++
	Result: Accepted
	Time:14 ms
	Memory:2072 kb
****************************************************************/