#include <iostream>
#include <stack>
#include <algorithm>
using namespace std;

int main(void) {
	char a;
	while((a=getchar()) != '\n'){
		if(isupper(a)){
			putchar(tolower(a));
		}else{
			putchar(toupper(a));
		}
	}
	cout << endl;
	return 0;
}