// #include <bits/stdc++.h>
#include <iostream>
#include <cmath>
#include <algorithm>
#include <map>
#include <unordered_map>
#include <vector>
#include <iomanip>
#include <string>
#include <queue>
#include <set>
#include <deque>
using namespace std;
#define int long long
#define endl "\n"
#define fi first
#define se second
const int M=1e9+7;
// const int inf = 3e9;
const int LOG=19;
const int N=2e3+5;
int n , m , c , w , k , t=1 , q=1 , x , y , z , l , r;
int dp[N][N][3];
void solve()
{
cin >> n >> x >> y;
if (x==1 or y==1){
dp[1][1][1]=1;
}
else{
dp[1][1][0]=1;
}
for (int i=1;i<n;i++){
for (int j=1;j<=i;j++){
if (x==i+1 or y==i+1){
for (int k=0;k<2;k++){
dp[i+1][j+1][k+1]+=dp[i][j][k];
dp[i+1][j+1][k+1]%=M;
dp[i+1][j][k+1]+=dp[i][j][k];
dp[i+1][j][k+1]%=M;
}
}
else{
for (int k=0;k<3;k++){
dp[i+1][j+1][k]+=dp[i][j][k]*(j+1-k);
dp[i+1][j+1][k]%=M;
// dp[i+1][j][k]+=dp[i][j][k]*(2*j-k);
dp[i+1][j-1][k]+=dp[i][j][k]*(j-1);
dp[i+1][j-1][k]%=M;
}
}
}
}
cout << dp[n][1][2] << endl;
}
signed main()
{
ios::sync_with_stdio(0);//DO NOT USE IN INTERACTIVE
cin.tie(0), cout.tie(0);//DO NOT USE IN INTERACTIVE
cout << fixed<<setprecision(9);
srand(time(0));
// int t=1;
// cin >> t;
for (int _=1;_<=t;_++){
solve();
q++;
}
}
