#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int MAXN=2e3+5;
const ll MOD = 1e9+7;
int N, S, T;
ll dp[MAXN][MAXN];
int main(){
cin >> N >> S >> T;
if(S > T){
swap(S,T);
}
if(N == 1){
cout << "1\n";
return 0;
}
dp[0][0] = 1;
for(int i=1;i<=N;i++){
for(int j=1;j<=N;j++){
if(i == S || i == T){
dp[i][j] = dp[i-1][j]+dp[i-1][j-1];
}else if(i > T){
dp[i][j] = (j-2)*dp[i-1][j-1]+j*dp[i-1][j+1];
}else if(i > S){
dp[i][j] = (j-1)*dp[i-1][j-1]+j*dp[i-1][j+1];
}else{
dp[i][j] = j*dp[i-1][j-1]+j*dp[i-1][j+1];
}/*
dp[i][j][0] = j*dp[i-1][j-1][0]+j*dp[i-1][j+1][0];
dp[i][j][1] = (j-1)*dp[i-1][j-1][1]+j*dp[i-1][j+1][1]+2*dp[i-1][j][0]+2*dp[i-1][j-1][0];
dp[i][j][2] = (j-2)*dp[i-1][j-1][2]+j*dp[i-1][j+1][2]+dp[i-1][j][1]+dp[i-1][j-1][1];*/
dp[i][j] %= MOD;
}
}
cout << dp[N][1] << '\n';
return 0;
}
/*
https://oj.uz/problem/view/CEOI16_kangaroo
A[i]>A[i-1]
2 1 5 3 4
(N-2)!
*/
