#include <bits/stdc++.h>
#define int long long
using namespace std;
const int N = 2005;
int dp[N][N];
const int mod = 1e9+7;
void add(int &a,int b){
a = (a + b) % mod;
}
int32_t main() {
int n,st,en,diff=0;
cin >> n >> st >> en;
dp[1][1] = 1;
for(int i = 1;i<=n+1;i++) {
for(int j = 1;j<=i;j++) {
if(i == st || i == en) {
add(dp[i+1][j],dp[i][j]);
add(dp[i+1][j+1],dp[i][j]);
} else {
add(dp[i+1][j+1],dp[i][j] * (j - (i > st) - (i > en) + 1)); // new cmp
if(j-1>=1)add(dp[i+1][j-1],dp[i][j] * (j-1)); // merge
}
// cerr << dp[i][j] << " ";
}
// cerr<<'\n';
}
cout << dp[n+1][1];
}
/*
no 3 can be increasing 2x or decreasing 2x
want to use the same update so force structure into the problme
*/
