from collections import *
from itertools import *
from functools import *
from heapq import *
import sys,math
input = sys.stdin.readline

N,M = map(int,input().split())

mod = 10**9 + 7
class combination():
    
    def __init__(self,N,p):
        
        
        self.fact = [1, 1]  # fact[n] = (n! mod p)
        self.factinv = [1, 1]  # factinv[n] = ((n!)^(-1) mod p)
        self.inv = [0, 1]  # factinv 計算用
        self.p = p
        
        for i in range(2, N + 1):
            self.fact.append((self.fact[-1] * i) % p)
            self.inv.append((-self.inv[p % i] * (p // i)) % p)
            self.factinv.append((self.factinv[-1] * self.inv[-1]) % p)
        

    def cmb(self,n, r):
        if (r < 0) or (n < r):
            return 0
        r = min(r, n - r)
        return self.fact[n] * self.factinv[r] * self.factinv[n-r] % self.p
        
C = combination(M+1,mod)

if N>M:
    print(1)
    exit()
if N==1:
    print(1)
    exit()
ans = 1
cnt = 1
while M - N*cnt >=0 :
    
    ans += C.cmb(M-cnt*(N-1),cnt)
    # print(cnt,C.cmb(M-cnt*(N-1),cnt))
    ans %= mod
    cnt += 1
print(ans)