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

int main(){
	char c;
	cin>>c;
	if(isupper(c)){
		c = c + 32;
	}else if(islower(c)){
		c = c - 32;
	}
	
	cout<<c;
}


/**************************************************************
	Problem: 1971
	User: admin
	Language: C++
	Result: Accepted
	Time:33 ms
	Memory:2072 kb
****************************************************************/