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

int main(void) {
  FILE *stdin = fopen("/dev/stdin", "r");
  if (!stdin) {
    perror("fopen(stdin)");
    exit(1);
  }
  FILE *stdout = fopen("/dev/stdout", "w");
  if (!stdin) {
    perror("fopen(stdout)");
    exit(1);
  }

  while (!feof(stdin)) {
    unsigned char x;

    fscanf(stdin,"%hhx ", &x);
    fwrite(&x, 1, 1, stdout);
  }
  fclose(stdout);
  fclose(stdin);
}