import sys
import math
def S(): return sys.stdin.readline().rstrip()
def I(): return int(sys.stdin.readline().rstrip())
def MI(): return map(int,sys.stdin.readline().rstrip().split())
def LI(): return list(map(int,sys.stdin.readline().rstrip().split()))
def LS(): return list(sys.stdin.readline().rstrip().split())

n,s = MI()
f = [1]
for i in range(1,s):
    f.append(f[i-1]*i)

l = list(range(1, s+1))
p = []

for i in range(s):
    tmp = n//f[s-1-i]
    p.append(l[tmp])
    l.remove(l[tmp])
    n = n%f[s-1-i]

q = []
for i in range(s):
    q.append(p.index(i+1)+1)

l = list(range(1, s+1))
ans = 0
for i in range(s):
    ans += (l.index(q[i]))*f[s-1-i]
    l.remove(q[i])

print(ans)