#include<bits/stdc++.h>
using namespace std;
#define int long long
#define tii tuple<int,int,int>
#define pii pair<int,int>
#define ff first
#define ss second
#define all(x) x.begin(),x.end()
#define allr(x) x.rbegin(),x.rend()
#define pb push_back
#define mp make_pair
const int maxn = 2e3+5, MOD=1e9+7;
int dp[maxn][maxn];
void solve(){
int n,cs,cf; cin >> n >> cs >> cf;
dp[0][0] = 1;
for(int k=1; k<=n; k++){
for(int c=1; c<=n; c++){
int p = (k>cs)+(k>cf);
// uniao (n_c2 - (k>cs) - (k>cf) jeitos) e criar (1 jeito)
dp[k][c] = (dp[k-1][c+1]*(c*(c+1) -p*c+(k==n && c==1)) + dp[k-1][c-1])%MOD;
if(k==min(cs,cf)){
// extensao (c jeitos) e criar (1 jeito)
dp[k][c] = (dp[k-1][c]*c + dp[k-1][c-1])%MOD;
}
if(k==max(cs,cf)){
// extensao (c-1 jeitos) e criar (1 jeito)
dp[k][c] = (dp[k-1][c]*(c-(k<n)) + dp[k-1][c-1])%MOD;
}
// cout << dp[k][c] << " ";
}
// cout << endl;
}
cout << dp[n][1] << '\n';
}
signed main(){
ios_base::sync_with_stdio(false); cin.tie(0);
int t=1;
// cin >> t;
while(t--){
solve();
}
}
