#include int main(void) { char ch; while((ch = getchar()) != -1) { /* a-z or A-Z? */ if((ch > 64 && ch < 91) || (ch > 96 && ch < 123)) { /* < N or < n? */ if(ch < 78 || (ch > 96 && ch < 110)) { putchar(ch+13); }else{ putchar(ch-13); } }else{ /* anything else */ putchar(ch); } } }