mod = 1000000007
N,K = map(int,input().split())
def cal(x,n):
if n == 1:
return x
cal2 = cal(x,n//2)
if n%2:
return cal2*cal2*x %mod
else:
return cal2*cal2 %mod
numer = denom = 1
for i in range(1,K+1):
numer = numer*(N+1-i) %mod
denom = denom*(i) %mod
print(numer*cal(denom,mod-2)%mod)
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