#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 2005;
const int mod = 1000000007;
ll n,s,e;
ll dp[N][N];
int main(){
ios_base::sync_with_stdio(false);
cin.tie(0);
/*freopen("kangaroo.in","r",stdin);
freopen("kangaroo.out","w",stdout);*/
cin >> n >> s >> e;
dp[0][0] = 1;
for(int i = 1; i <= n; i++){
for(ll j = 1; j <= i; j++){
if(i == s){
/// create a new component at the beginning or just put it at the beginning
dp[i][j] += dp[i-1][j-1]+dp[i-1][j];
dp[i][j] %= mod;
continue;
}
if(i == e){
/// create a new component at the end or just put it at the end
dp[i][j] += dp[i-1][j-1]+dp[i-1][j];
dp[i][j] %= mod;
continue;
}
/// create a new component
dp[i][j] += (dp[i-1][j-1]*(j-(i > s)-(i > e)))%mod;
dp[i][j] %= mod;
/// we can't put new elements at the ends or the beginnings of existing components
/// merge two components - always valid
dp[i][j] += (dp[i-1][j+1]*j)%mod;
dp[i][j] %= mod;
}
}
cout << dp[n][1] << endl;
}
