#include<bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define ins insert
#define pb push_back
#define foru(i,a,b) for(int i=a;i<=b;i++)
#define ford(i,a,b) for(int i=a;i>=b;i--)
#define pii pair<int,int>
#define pll pair<ll,ll>
#define int ll
using namespace std;
int const mod=1e9+7;
int n,cs,cf,cnt;
int dp[2005][2005];
signed main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);cout.tie(0);
// freopen(".inp","r",stdin);
// freopen(".out","w",stdout);
cin>>n>>cs>>cf;
dp[1][1]=1;
for(int i=1;i<=n;i++)
{
if(i==cs||i==cf) cnt++;
for(int j=1;j<i;j++)
{
if(i==cs||i==cf)
{
dp[i][j+1]+=dp[i-1][j];
dp[i][j+1]%=mod;
dp[i][j]+=dp[i-1][j];
dp[i][j]%=mod;
}
else
{
dp[i][j+1]+=(j+1-cnt)*dp[i-1][j]%mod;
dp[i][j+1]%=mod;
dp[i][j-1]+=(j-1)*(dp[i-1][j])%mod;
dp[i][j-1]%=mod;
}
}
}
cout<<(dp[n][1]%mod+mod)%mod;
}
/*
em thi cho du co khoc
cung se den ngay phai quen
thien duong van cho ngay em den
*/
