def f(n):
    r=1
    for i in range(1,n+1):
        r*=i
    return r

from itertools import permutations

N,S=map(int,input().split())
T=[1]*(S+1)

K=f(S)
X=[0]*(S+1)

P=[0]
for j in range(S,0,-1):
    K//=j

    a,N=divmod(N,K)

    i=1
    while True:
        if T[i]==1 and a==0:
            break
        elif T[i]==1 and a!=0:
            a-=1
        i+=1

    T[i]=0
    P.append(i)

Q=[0]*(S+1)
for i in range(1,S+1):
    Q[P[i]]=i

A=0
T=[1]*(S+1)

for i in range(1,S+1):
    K=f(S-i)
    for j in range(1,Q[i]):
        if T[j]==1:
            A+=K
    T[Q[i]]=0
print(A)