#include <bits/stdc++.h>
using namespace std;
template<class A, class B> bool maximize(A& x, B y) {if (x < y) return x = y, true; else return false;}
template<class A, class B> bool minimize(A& x, B y) {if (x > y) return x = y, true; else return false;}
#define all(a) a.begin(), a.end()
#define pb push_back
#define pf push_front
#define fi first
#define se second
// #define int long long
typedef long long ll;
typedef unsigned long long ull;
typedef double db;
typedef long double ld;
typedef pair<db, db> pdb;
typedef pair<ld, ld> pld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<ll, int> plli;
typedef pair<int, ll> pill;
const int MAX_N = 2e3 + 5;
const int mod = 1e9 + 7; // 998244353
int n, s, t;
int dp[MAX_N][MAX_N];
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> s >> t;
dp[1][1] = 1;
int cnt = 0;
for (int i = 1; i < n; i++) {
if (i == s || i == t) cnt++;
if (i + 1 == s || i + 1 == t) {
for (int j = 1; j <= i; j++) {
if (!dp[i][j]) continue;
// tao ra 1 tplt rieng
(dp[i + 1][j + 1] += dp[i][j]) %= mod;
// ghep vao 1 tplt
(dp[i + 1][j] += dp[i][j]) %= mod;
}
}
else {
for (int j = 1; j <= i; j++) {
// tao ra 1 tplt rieng -> j + 1 - cnt vi tri
if (j + 1 - cnt > 0) {
(dp[i + 1][j + 1] += 1ll * dp[i][j] * (j + 1 - cnt) % mod) %= mod;
}
// ket noi 2 tlpt nao do -> j - 1 vi tri
(dp[i + 1][j - 1] += 1ll * dp[i][j] * (j - 1) % mod) %= mod;
}
}
}
cout << dp[n][1];
return 0;
}
/*
*/
