#include <bits/stdc++.h>
using namespace std;
const int MOD = 1e9 + 7;
int add (int a, int b) {
a += b; if (a >= MOD) a -= MOD;
return a;
}
int sub (int a, int b) {
a -= b; if (a < 0) a += MOD;
return a;
}
int mul (int a, int b) {
return (a * 1ll * b) % MOD;
}
typedef long long ll;
int dp[2003][2003], n, s, t;
void solve () {
cin >> n >> s >> t;
dp[1][1] = 1;
for (int i = 2; i <= n; i++) {
for (int j = 1; j <= n; j++) {
if (i == s || i == t) {
dp[i][j] = add(dp[i - 1][j - 1], dp[i - 1][j]);
} else {
dp[i][j] = mul(dp[i - 1][j + 1], j);
dp[i][j] = add(dp[i][j], mul(dp[i - 1][j - 1], j - (i > s) - (i > t)));
}
}
}
cout << dp[n][1] << '\n';
}
signed main () {
ios::sync_with_stdio(0); cin.tie(0);
int tc = 1; //cin >> tc;
while (tc--) solve();
}
