#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
  int ch;

  if (argc < 2) {
    fprintf(stderr,"Usage: cypher <key>\n");
    exit(1);
  }
  srand(atoi(argv[1]));
  
  while((ch = getchar()) != EOF) {
    putchar(ch ^ (rand() & 0xFF));
  }
  return 0;
}