//le privesc ca fiind orientate
#include <bits/stdc++.h>
#include <sys/time.h>
using namespace std;
using i64=long long;
#define UNUSED -1
#define all(x) x.begin(),x.end()
#define pb push_back
const int mod=1e9+7,inf=1e9+1;
const i64 INF=1e18;
int add(int x,int y)
{
return (x+y)%mod;
}
void add_self(int& x,int y)
{
x+=y;
if(x>=mod)
{
x-=mod;
}
}
int prod(int x,int y)
{
return (1LL*x*y)%mod;
}
mt19937 rng(69);
const int N=2000;
int dp[N][N+2];
int signatura(int x)
{
if(x>=0)
{
return 1;
}
return 0;
}
int main()
{
int n,start,finish;
cin>>n>>start>>finish;
start--;
finish--;
dp[0][1]=1;
for(int i=1;i<n;i++)
{
for(int j=1;j<=i+1;j++)
{
if(i==start || i==finish)
{
//adaug ca componenta noua
add_self(dp[i][j],dp[i-1][j-1]);
//leg cu cv
add_self(dp[i][j],dp[i-1][j]);
}
else
{
//leg 2
add_self(dp[i][j],prod(dp[i-1][j+1] , j));
//adaug una noua
add_self(dp[i][j],prod(dp[i-1][j-1] , j-(i>start)-(i>finish)));
}
}
}
cout<<dp[n-1][1];
}
