import math
n, s = map(int, input().split())

# 元の順列の復元
P = []
num = list(range(s))
for i in reversed(range(s)):
    d, n = divmod(n, math.factorial(i))
    P.append(num.pop(d))

# 逆置換作成
R = [-1] * s
for i, p in enumerate(P):
    R[p] = i

# 辞書順の位置
ans = 0
num = list(range(s))
for i, v in enumerate(R, 1):
    ans += math.factorial(s - i) * num.index(v)
    num.pop(num.index(v))

print(ans)