// Born_To_Laugh - Hughie Do
#include <bits/stdc++.h>
#define alle(AC) AC.begin(), AC.end()
#define fi first
#define se second
using namespace std;
typedef long long ll;
[[maybe_unused]] const int MOD = 1e9 + 7, INF = 1e9 + 7;
const int maxn = 2010;
int n, cs, cf;
ll dp[maxn][maxn];
void solve(){
cin >> n >> cs >> cf;
dp[0][0] = 1;
int cnt = 0;
for(int i=1; i<=n; ++i){
if(i == cs) cnt++;
if(i == cf) cnt++;
for(int j=1; j<=i; ++j){
if(i == cs || i == cf){
dp[i][j] += dp[i - 1][j - 1] + dp[i - 1][j];
dp[i][j] %= MOD;
continue;
}
dp[i][j] += dp[i - 1][j - 1] * max(0, j - cnt);
dp[i][j] += dp[i - 1][j + 1] * j;
}
}
cout << dp[n][1] << '\n';
}
signed main(){
// freopen("inp.txt", "r", stdin);
// freopen("out.txt", "w", stdout);
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
solve();
}
