def printHex(n):
    if n > 15:
        printHex(n // 16)
    nn = n % 16
    if nn == 10:
      print("A", end="")
    elif nn == 11:
      print("B", end="")
    elif nn == 12:
      print("C", end="")
    elif nn == 13:
      print("D", end="")
    elif nn == 14:
      print("E", end="")
    elif nn == 15:
      print("F", end="")
    else:
      print(nn, end="")
    
n = int(input())
printHex(n)