/*
* author: NeroZein
* created: 23.01.2023 08:16:46
*/
#include <bits/stdc++.h>
using namespace std;
#ifdef Nero
#include "Deb.h"
#else
#define deb(...)
#endif
const int md = 1e9+7;
inline int add(int a, int b){
a += b;
if(a >= md){
a -= md;
}
return a;
}
inline int mul(int a, int b){
return (int)((long long) a * b % md);
}
signed main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n, cs, cf;
cin >> n >> cs >> cf;
vector<int> dp(n);
dp[1] = 1;
for (int i = 2; i <= n; ++i){
vector<int> pd(n);
for (int j = 1; j < n; ++j){
//endpoint either
if(i == cs || i == cf){
//alone or to the left or right to existing set
pd[j] = add(dp[j-1], dp[j]);
}
else{
//merge two sets or start a new one
pd[j] = add(mul(j, dp[j+1]), mul(j - (i > cs) - (i > cf), dp[j-1]));
}
}
swap(dp, pd);
}
cout << dp[1];
}
