N,S=map(int,input().split())

F=[1,1]
for i in range(1,20):
    F.append(F[-1]*i)

def calc(A):
    if len(A)==1:
        return 0
    compression_dict={a: ind for ind, a in enumerate(sorted(set(A)))}
    A=[compression_dict[a] for a in A]
    #print(A)

    return F[len(A)]*A[0]+calc(A[1:])

A=[]
USE=[0]*S
for i in range(S):
    uind=0
    while USE[uind]==1:
        uind+=1
        
    while N:
        if N>=F[S-i]:
            uind+=1
            N-=F[S-i]
        else:
            break
            
        while USE[uind]==1:
            uind+=1

    A.append(uind)
    USE[uind]=1

#print(A)
B=[]
for i in range(S):
    B.append(A.index(i))

print(calc(B))