#include <stdio.h>

char codes[]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};

int main () {
  char line[256];
  int i, val, digit;
  while (fgets(line, 255, stdin)) {
    val = atoi(line);
    for (i = 28; i >= 0; i=i-4) {
      digit = (val >> i) & 0xF;
      putchar(codes[digit]);
    }
    putchar('\n');
  }
  return 0;
}