#include <bits/stdc++.h>
using namespace std;
#define ll long long
const ll mod = 1e9 + 7;
int n, s, e;
ll dp[2005][2005];
ll solve(int x, int y){
memset(dp, 0, sizeof(dp));
dp[n + 1][0] = 1;
int oc = 0;
for(int i = n; i >= 1; i --){
for(int j = 1; j <= n - i + 1; j ++){
if(i == s) (dp[i][j] += dp[i + 1][j - x]) %= mod;
else if(i == e) (dp[i][j] += dp[i + 1][j - y]) %= mod;
else (dp[i][j] += (dp[i + 1][j - 1] * 1ll * (j - oc) + dp[i + 1][j + 1] * 1ll * j) % mod) %= mod;
}
if(i == e || i == s) oc ++;
}
return dp[1][1];
}
int main(){
cin.tie(0) -> sync_with_stdio(0);
cin >> n >> s >> e;
cout << (solve(0, (n + 1) % 2) + solve(1, n % 2)) % mod << endl;
}
