#include<bits/stdc++.h>
using namespace std;
#define int long long
#define ll long long
#define i128 int128
#define ii pair<int,int>
#define ld long double
#define vi vector<int>
#define vvi vector<vi>
#define vii vector<pair<int,int>>
#define FOR(i,a,b) for (int i=a;i<=b;i++)
#define FOR1(i,a,b,c) for (int i=a;i<=b;i+=c)
#define REP(i,a,b) for (int i=a;i>=b;i--)
#define REP1(i,a,b,c) for(int i=b;i>=a;i-=c)
#define endh '\n';
#define len(a) a.length()
#define pb(c) push_back(c)
#define elif else if
#define ppb() pop_back()
#define rong std::npos
#define all(c) (c.begin(),c.end())
#define Z int
#define R double
#define lcm(a,b) ((int) (a/__gcd(a,b))*b)
#define mk(a,b) make_pair(a,b)
Z dx4[]={-1,1,0,0};
Z dy4[]={0,0,1,-1};
string co="YES",khong="NO";
const int mod=1e9+7;
Z dp[2003][2003];
Z mul(Z a,Z b)
{
return (a*b)%mod;
}
void add(Z &a,Z b)
{
a+=b;
a%=mod;
}
Z n,s,t;
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
cin>>n>>s>>t;
dp[1][1]=1;
FOR(i,2,n){
FOR(j,1,n){
if (i==s || i==t){
add(dp[i][j+1],dp[i-1][j]);
add(dp[i][j],dp[i-1][j]);
}
else{
add(dp[i][j],mul(dp[i-1][j-1],j-(i>s)-(i>t)));
add(dp[i][j-1],mul(dp[i-1][j],j-1));
}
}
}
cout<<dp[n][1];
}
