#include <bits/stdc++.h>
// #pragma GCC optimize("Ofast,no-stack-protector,unroll-loops")
// #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
// #define ll long long
#define int long long
#define pii pair<int, int>
#define all(v) v.begin(), v.end()
using namespace std;
const int oo = 1e9 + 9;
const int MAX = 2000 + 5, LOGMAX = 20, B = 441, MOD = 1e9 + 7;
int dp[MAX][MAX];
void solve(){
int n, cs, cf; cin >> n >> cs >> cf;
dp[1][1] = 1;
for(int i = 2; i <= n; i++){
for(int j = 1; j <= i; j++){
if(i == cs || i == cf){
dp[i][j] += dp[i - 1][j];
dp[i][j] += dp[i - 1][j - 1];
}
else{
dp[i][j] += dp[i - 1][j - 1] * (j - (i > cs) - (i > cf)) % MOD;
dp[i][j] += dp[i - 1][j + 1] * j % MOD;
}
dp[i][j] %= MOD;
}
}
cout << dp[n][1] << '\n';
}
signed main(){
ios::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
int t = 1;
// cin >> t;
while(t--) solve();
}
