#include<iostream>
#include<cstdio>
#include<cctype>
#include<string.h>
#include<math.h>
#include<cmath>
#include<algorithm>
#include<iomanip>
using namespace std;
int main()
{
	char a;
	cin>>a;
	if(a>='A'&&a<='Z')
	{
		cout<<char(a+32);
	} 
	else if(a>='a'&&a<='z')
	{
		cout<<char(a-32);
	}
	else
	{
		cout<<a;
	}
	return 0;
}