#include <iostream>
#include <cstdio>
#include <string>
using namespace std;
#define a 'a'
#define z 'z'
#define A 'A'
#define Z 'Z'
int main(){
	string s;
	cin>>s;
	for(int i=0;i<(int)s.size();i++){
		if(A<=s[i]&&s[i]<=Z)	printf("%c",(char)s[i]-A+a);
		else if(a<=s[i]&&s[i]<=z)	printf("%c",s[i]-a+A);
	}
	cout<<endl;
	return 0;
}