B = 10**9 + 7

n,m=map(int,input().split())

blanks = n - m
blank_p=1
for i in range(1, blanks+1):
    blank_p *= (n+1-i)/(i)
    blank_p%=B
cp = 1
for i in range(1, m+1):
    cp *= i 
    cp %= B

print(int(cp*blank_p%B))