//Desinged by AzeTurk810 Open source
#include <bits/stdc++.h>
using namespace std;
# define ull unsigned long long
# define hurryup ios_base::sync_with_stdio(false);cin.tie(0);cout.tie(0)
# define endl '\n'
# define pb push_back
# define INF 1e10
# define vbol vector<bool>
# define vint vector<int>
# define ll long long
# define int long long
# define mod 1000000007
signed main()
{
int n,cs,cf,fixed = 0;
cin>>n>>cs>>cf;
vector<vector<int>>dp (n + 1,vector<int>(n + 1,0));
dp[1][1] = 1;
for(int i=1;i<=n;i++)
{
if(cs == i || cf == i) fixed++;
for(int j=1;j<=n;j++)
{
if(cs == i || cf == i)
{
dp[i][j + 1] += dp[i - 1][j]%mod;
dp[i][j] += (dp[i - 1][j])%mod;
}
else
{
dp[i][j + 1] += (dp[i - 1][ j ] * (j-fixed + 1))%mod;
dp[i][ j -1] +=( dp[i -1 ][j] *(j - fixed + 1))%mod;
}
}
}
cout<<dp[n][1]<<endl;
}
