#include <iostream>

using namespace std;

int main(){
    int data;
    cout << "Enter Message to ROT13: " << endl;
    while(cin && cin.peek() != EOF){
	data = cin.get();
	if(data >= 'A' && data <= 'Z'){
	    data = ((data - 'A') + 13) % 26 + 'A';
	}else if(data >= 'a' && data <= 'z'){
	    data = ((data - 'a') + 13) % 26 + 'a';
	}
	cout << char(data);
    }
}