# 36진법
# ZZZZZ
# -> (Z x 36**4) + (Z x 36**3) + (Z x 36**2) + (Z x 36**1)+ (Z x 36**0)
n, b = input().split()
n = n[::-1]
arr = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ'
res = 0
for i, num in enumerate(n):
res += ((int(b)**i) * (arr.index(num)))
print(res)
cf) 문자열로만 arr 만든 후 index + 10
n, b = input().split()
n = n[::-1]
arr = 'ABCDEFGHIJKLMNOPQRSTUVWXYZ'
res = 0
for i, num in enumerate(n):
res += ((int(b)**i) * (arr.index(num)+10))
print(res)