numOx = input().strip() values = { 'A':10, 'B':11, 'C':12, 'D':13, 'E':14, 'F':15 } sums = 0 j=0 for i in range(len(numOx)-1,1,-1): if numOx[i] in "0123456789": sums = int(numOx[i])*(16**j) + sums else: number = values[numOx[i]] sums = number*(16**j) + sums j += 1 print(sums)