Anonymous

#include <stdio.h>

int main(void) {
        char ch; 
        while((ch = getchar()) != -1) {
                if((ch > 64 && ch < 91) || (ch > 96 && ch < 123)) {
                        if(ch < 78 || (ch > 96 && ch < 110)) {
                                putchar(ch+13);
                        }else{
                                putchar(ch-13);
                        }   
                }else{
                        putchar(ch);
                }   
        }   
}