mod=10**9+7
n,m=map(int,input().split())
ans=0
tmp=1
for i in range(n):
    tmp*=(m-i)
    tmp%=mod
ans+=tmp
for i in range(m,n,-1):
    tmp*=pow(i,mod-2,mod)
    tmp*=(i-n)
    tmp%=mod
    ans+=tmp
    ans%=mod
div=1
for i in range(1,n+1):
    div*=i
    div%=mod
div=pow(div,mod-2,mod)
print((ans*div)%mod)