B = 10**9 + 7

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

blanks = n - m
blank1=1
blank2=1
for i in range(1, blanks+1):
    blank1 *= (n+1-i) % B
    blank2 *= (i) % B

blank_p = int(blank1 / blank2)

cp = 1
for i in range(1, m+1):
    cp *= i 
    cp %= B

print(cp*blank_p%B)