https://www.acmicpc.net/problem/11005
N, B = input().split()
num = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'
N = N[::-1]
result = 0
for i in range(len(N)) :
result += (int(B)**i) * (num.index(N[i]))
print(result)
N, B = input().split()
print(int(N, int(B)))