#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vii;
typedef pair<int,int> pi;
typedef vector<pi> pii;
typedef tuple<int,int,int> tii;
typedef vector<ll> li;
typedef vector<li> lii;
#define REP(i,a,b) for(int i=a;i<b;i++)
#define F first
#define S second
#define PB push_back
#define MP make_pair
#define LSOne(s) ((s)&(-s))
ll INF=1000000000000000010;
int inf=1e9+10;
ll M=1e9+7;
int main() {
int n,x,y;cin>>n>>x>>y;
x--;y--;
vector<vector<ll>> dp(n,vector<ll>(n+1,0));
dp[0][1]=1;
REP(i,1,n){
if(i==x||i==y)REP(j,1,n+1)dp[i][j]=(dp[i-1][j]+dp[i-1][j-1])%M;
else REP(j,1,n)dp[i][j]=(dp[i-1][j+1]*j+dp[i-1][j-1]*(j-(i<x)-(i<y)))%M;
}
cout<<dp[n-1][1];
}
