#include <bits/stdc++.h>

using namespace std;

const int maxn=2005;
const int mod=1e9+7;
int dp[maxn][maxn];
int fac[maxn],inv[maxn];

int qpow(int x,int y){
	int res=1;
	while(y){
		if(y&1) res=1ll*res*x%mod;
		x=1ll*x*x%mod;
		y>>=1;
	}
	return res;
}
inline void init(int n){
	fac[0]=inv[0]=1;
	for(int i=1;i<=n;i++) fac[i]=1ll*fac[i-1]*i%mod;
	inv[n]=qpow(fac[n],mod-2);
	for(int i=n-1;i>=1;i--) inv[i]=1ll*inv[i+1]*(i+1)%mod;
}

int C(int n,int m){
	if(n<m||m<0) return 0;
	return 1ll*fac[n]*inv[m]%mod*inv[n-m]%mod;
}

int main(){
	
	int n,s,t;
	
	scanf("%d %d %d",&n,&s,&t);
	
	init(n);
	
	dp[n][1]=1;
	
	for(int i=n-1;i>=1;i--){
		for(int j=1;j<=(n-i+1);j++){
			if(i==s||i==t){
				dp[i][j]=(dp[i+1][j]+dp[i+1][j-1])%mod;
				continue;
			}
			if(i<s&&i<t) dp[i][j]=(1ll*dp[i][j]+1ll*dp[i+1][j+1]*j%mod+1ll*dp[i+1][j-1]*(j-2)%mod)%mod;
			else if(i<s||i<t) dp[i][j]=(1ll*dp[i][j]+1ll*dp[i+1][j+1]*j%mod+1ll*dp[i+1][j-1]*(j-1)%mod)%mod;
			else dp[i][j]=(1ll*dp[i][j]+1ll*dp[i+1][j+1]*j%mod+1ll*dp[i+1][j-1]*j%mod)%mod;
		}
	}
	
	printf("%d\n",dp[1][1]);
	
	return 0;
}