#include <bits/stdc++.h>
typedef long long ll;
using namespace std;
const ll mod = 1e9 + 7;
int add(int a, int b) { return (a + b) % mod; }
int mul(int a, int b) { return (a * 1ll * b) % mod; }
void upd(int &a, int b) { a = (a + b) % mod; }
int main()
{
ios::sync_with_stdio(false);
cin.tie(0);
int n, s, f;
cin >> n >> s >> f;
vector<vector<int> > dp(n+2, vector<int>(n+2, 0)); // dp[number of vertices][number of components]
dp[0][0] = 1;
for (int i = 1; i <= n; i++) for (int j = 1; j <= n; j++)
{
if (i == s || i == f)
{
upd(dp[i][j], dp[i-1][j-1]); // bud pridame jeden novy komponent
int c = (j - (s < i) - (f < i));
if (i == n) c++;
upd(dp[i][j], mul(dp[i-1][j], c)); // alebo sa napojime na nejaky predosly
}
else
{
upd(dp[i][j], dp[i-1][j-1]); // bud pridame jeden novy komponent
// ideme spojit dva ine komponenty. s a f mozeme (dokonca musime) spojit len ak i == n.
if (i == n)
{
upd(dp[i][j], dp[i-1][j+1]);
}
else
{
int c1 = (s < i) + (f < i), c2 = j + 1 - c1;
int val = (c2 * (c2 - 1)) + c1 * c2;
upd(dp[i][j], mul(dp[i-1][j+1], val));
}
}
//cout << dp[i][j] << " ";
//if (j == n) cout << endl;
}
cout << dp[n][1] << "\n";
return 0;
}
