/*
_____ _ ____ _
|_ _| |__ ___/ ___| ___ _ __ | |_ _ __ ___
| | | '_ \ / _ \___ \ / _ \ '_ \| __| '__/ _ \
| | | | | | __/___) | __/ | | | |_| | | (_) |
|_| |_| |_|\___|____/ \___|_| |_|\__|_| \___/
*/
#include <bits/stdc++.h>
// #pragma GCC optimize("O3")
using namespace std;
#define ll long long
ll mod = 1e9+7;
ll binpow(ll a, ll b)
{
ll res = 1;
while (b>0)
{
if (b&1)
res = (res*a)%mod;
a = (a*a)%mod;
b>>=1;
}
return res;
}
ll gcd(ll x, ll y)
{
if (y==0)
return x;
return gcd(y, x%y);
}
ll dp[2005][2005];
void solve()
{
ll n,s,f;
cin>>n>>s>>f;
dp[1][1] = 1;
ll fix=0;
for (int i=1 ; i<=n ;i++)
{
for (int j=1 ; j<i ; j++)
{
if (i==s or i==f)
{
fix++;
dp[i][j+1] = (dp[i][j+1]+dp[i-1][j])%mod;
dp[i][j] = (dp[i][j]+dp[i-1][j])%mod;
}
else
{
dp[i][j+1] = (dp[i][j+1]+(j+1-fix)*dp[i-1][j])%mod;
dp[i][j-1] = (dp[i][j-1]+(j-1)*dp[i-1][j])%mod;
}
}
}
cout<<dp[n][1]<<endl;
}
int main()
{
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
ll tt = 1;
// cin>>tt;
while (tt--)
{
solve();
}
return 0;
}
