#include <bits/stdc++.h> using namespace std; #define int long long const int mod = 1e9 + 7; int prime[1000010], idx, st[1000010]; void get_primes(int n) { for (int i = 2; i <= n; i++) { if (!st[i]) prime[idx++] = i; for (int j = 0; prime[j] <= n / i; j++) { st[prime[j] * i] = 1; if (i % prime[j] == 0) break; } } } void solve() { int n, m; cin >> n >> m; get_primes(max(n, m)); vector<int> cnt(n + 10); //函数:求x的阶乘中,所有质因子出现了多少次 f为1代表加上次数 f为-1代表减去次数 auto get = [&](int x, int f) { for (int i = 0; i < idx; i++) { int t = x, p = prime[i]; if (p > x) break; while (t / p >= 1) { cnt[p] += f * t / p; t /= p; } } }; get(n, 1), get(m, -1), get(n - m, -1); int ans = 1; for (int i = 2; i <= n; i++) { ans = ans * (cnt[i] + 1) % mod; } cout << ans << endl; } signed main() { int t = 1; ios::sync_with_stdio(false), cin.tie(0), cout.tie(0); // cin>>t; while (t--) solve(); return 0; }