#include <bits/stdc++.h>
using namespace std;
const int N = 2e3 + 5 , mod = 1e9 + 7;
int n , s , t , dp[N][N] , ans;
int modit(int a)
{
if(a >= mod)
return a - mod;
return a;
}
void solve(int st , int fn)
{
memset(dp , 0 , sizeof dp);
dp[0][0] = 1;
int slm = 0;
for(int i = 1 ; i <= n ; i++)
{
if(i == s)
{
for(int j = 1 ; j <= n ; j++)
dp[i][j] = dp[i - 1][j - st];
slm++;
continue;
}
if(i == t)
{
for(int j = 1 ; j <= n ; j++)
dp[i][j] = dp[i - 1][j - fn];
slm++;
continue;
}
for(int j = 1 ; j <= n ; j++)
{
dp[i][j] = 1LL * dp[i - 1][j - 1] * max(0 , j - slm) % mod;
dp[i][j] = modit(dp[i][j] + 1LL * dp[i - 1][j + 1] * j % mod);
}
}
ans = modit(ans + dp[n][1]);
}
signed main()
{
ios::sync_with_stdio(false);
cin.tie(0); cout.tie(0);
cin >> n >> s >> t;
int ty = (n & 1 ? 0 : 1);
solve(1 , 1 ^ ty);
solve(0 , 0 ^ ty);
cout << ans << '\n';
return 0;
}
