#include <bits/stdc++.h>
using namespace std;
using lint = long long;
const int MAX_N = 2e3 + 5;
const lint MOD = 1e9 + 7;
int n;
int s, f;
lint mod(lint x) {
return x % MOD;
}
lint dp[MAX_N][MAX_N];
void do_dp() {
dp[1][1] = 1;
for (int i = 1; i < n; i++) {
for (int c = 1; c <= n; c++) {
if ((i + 1) == s || (i + 1) == f) {
dp[i + 1][c + 1] = mod(dp[i + 1][c + 1] + dp[i][c]);
dp[i + 1][c] = mod(dp[i + 1][c] + dp[i][c]);
continue;
}
lint mult = c + 1;
mult -= (bool) (i + 1 > s);
mult -= (bool) (i + 1 > f);
dp[i + 1][c + 1] = mod(dp[i + 1][c + 1] + mod(dp[i][c] * mult));
dp[i + 1][c - 1] = mod(dp[i + 1][c - 1] + mod(dp[i][c] * (c - 1)));
}
}
}
int main() {
// freopen("kangaroo.in", "r", stdin);
cin >> n >> s >> f;
if (s > f) swap(s, f);
do_dp();
cout << dp[n][1] << '\n';
// for (int i = 1; i <= n; i++)
// for (int c = 1; c <= n; c++)
// cout << i << " " << c << ": " << dp[i][c] << endl;
}
