#include"bits/stdc++.h"
using namespace std;
#define ll long long
#define endl "\n"
#define fastio ios_base::sync_with_stdio(false)
#define inf LLONG_MAX
const ll mod=1e9+7;
const int lmt=2e3+10;
ll dp[lmt][lmt];
int main(){
fastio;
int n,cs,cf;
cin>>n>>cs>>cf;
if(cs>cf) swap(cs,cf);
dp[1][1]=1;
int blok=(1==cs || 1==cf);
for(int i=1;i<n;i++){
if(i+1==cs || i+1==cf) blok++;
for(int j=1;j<=n;j++){
if(i+1==cs || i+1==cf){
dp[i+1][j]=(dp[i+1][j]+dp[i][j])%mod;
dp[i+1][j+1]=(dp[i+1][j+1]+dp[i][j])%mod;
continue;
}
dp[i+1][j+1]=(dp[i+1][j+1]+(dp[i][j]*(j+1-blok))%mod)%mod;
if(j-1>0) dp[i+1][j-1]=(dp[i+1][j-1]+(dp[i][j]*(j-1))%mod)%mod;
}
}
cout<<dp[n][1]<<endl;
return 0;
}
