#include <bits/stdc++.h> using namespace std; // #pragma GCC optimize("Ofast") // #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma") // #pragma GCC optimize("unroll-loops") #define ll long long #define int128 __int128_t #define pii pair<int, int> #define int long long #define pb push_back #define F first #define S second #define all(v) (v).begin(), (v).end() #define rall(v) (v).begin(), (v).end() #define MOD 1000000007 #define INF (ll)1e18 #define RINF (ll) - 1e18 void cinv(vector<int> &a, int n) { for (int i = 0; i < n; i++) { cin >> a[i]; } } void coutv(vector<int> &a, int n) { for (int i = 0; i < n; i++) { cout << a[i] << " "; } } void solve() { int n, a, b; cin >> n >> a >> b; vector<int> c; for (int i = 1; i <= n; i++) { if (i != a && i != b) c.push_back(i); } vector<int> d(n + 1, 1); int r = 0; for (int i = 0; i < c.size(); i++) { long long q = c.size() - i - 1; long long w = i; long long h = 1; if (c[i] > a) { h = (h * w); } else { h = (h * q); } // cout << h << endl; if (c[i] > b) { h = (h * w); } else { h = (h * q); } // cout << h << endl; if (q > 0 && c.size() > 2) { h = (h * q * (q - 1) * (c.size() - 2)); } // cout << h << endl; if (w > 0 && c.size() > 2) { h = (h * w * (w - 1) * (c.size() - 2)); } // cout << h << endl; r += h % MOD; // cout << h << endl; } cout << r << endl; } signed main() { ios_base::sync_with_stdio(false); cin.tie(NULL); int t = 1; // cin >> t; while (t--) { solve(); } } // 5 2 3 // 2 // 1 - 2. 4 - 1. 5 - 2 // 1 - 2 4 - 0 5 - 2 // 1 - 2 4 - 1 5 - 2 // 3 // 32