#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
using namespace std;
const ll MOD=1e9+7;
ll N,x,y,dp[2005][2005];
int main(){
cin>>N>>x>>y;
memset(dp,0,sizeof(dp));
dp[0][0]=1;
for(int i=0;i<=N-1;i++){
for(int j=0;j<=N-1;j++){
ll cur=dp[i][j];
ll e=0;
if(i>=x){
e++;
}
if(i>=y){
e++;
}
if(i==x-1||i==y-1){
dp[i+1][j+1]+=cur;
if(i==N-1&&e==1&&j==1){
dp[i+1][j]+=cur;
}
else{
dp[i+1][j]+=(j-e)*cur;
}
dp[i+1][j+1]%=MOD;
dp[i+1][j]%=MOD;
}
else{
dp[i+1][j+1]+=cur;
if(j>0){
if(i==N-1){
dp[i+1][j-1]+=cur;
}
if(e>0&&(j-e)>0){
dp[i+1][j-1]+=e*(j-e)*cur;
}
if((j-e)>=2){
dp[i+1][j-1]+=(j-e)*(j-e-1)*cur;
}
}
dp[i+1][j+1]%=MOD;
dp[i+1][j-1]%=MOD;
}
}
}
cout<<dp[N][1]<<endl;
}
