import sys
input = sys.stdin.readline

N,K=map(int,input().split())
mod=10**9+7

FACT=[1]
for i in range(1,3*10**5+1):
    FACT.append(FACT[-1]*i%mod)

FACT_INV=[pow(FACT[-1],mod-2,mod)]
for i in range(3*10**5,0,-1):
    FACT_INV.append(FACT_INV[-1]*i%mod)

FACT_INV.reverse()

def Combi(a,b):
    if 0<=b<=a:
        return FACT[a]*FACT_INV[b]%mod*FACT_INV[a-b]%mod
    else:
        return 0

ANS=0

j=max(0,N-K)

X=1
for i in range(K-N+1+j,K+1+j):
    X=X*i%mod

INV=pow(FACT[N],mod-2,mod)
ANS=X*Combi(N-1,j)*INV%mod

#print(X,j,ANS)

for i in range(j+1,N):
    X=X*(K+i)*pow((K+i-N),mod-2,mod)%mod

    ANS+=X*Combi(N-1,i)*INV%mod

print(ANS%mod)