#include <iostream>
using namespace std;

const int mod = 1e9 + 7;
int f[2010][2010];

int add(int x, int y)
{
    return (x += y) < mod ? x : x - mod;
}

int main()
{
    int n, s, t;
    cin >> n >> s >> t;
    f[0][0] = 1;
    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j <= n; j++)
        {
            if (i == s || i == t) f[i][j] = add(f[i - 1][j - 1], f[i - 1][j]);
            else f[i][j] = add(1ll * f[i - 1][j + 1] * j % mod, 1ll * f[i - 1][j - 1] * (j - (i > s) - (i > t)) % mod);
        }
    }
    cout << f[n][1] << endl;
    return 0;
}