/*
dp[node][state];
state 0 : the node before me is a server
state 1 : the node before me isn't a server but it's covered by a server
state 2 : the node before me is a server but it's not covered by a server
*/
#include <bits/stdc++.h>
using namespace std;
using ii = pair<int,int>;
using ll = long long;
const int mod = 1e9 + 7;
const int N = 2005;
inline void fmin(int &x, int y){if(x > y)x=y;}
inline void fmax(int &x, int y){if(x < y)x=y;}
inline void add(int &x, int y){if((x+=y) >= mod)x-=mod;}
int n, cs, cf;
int dp[N][N];
int main(){
#ifdef ONLINE_JUDGE
ios_base::sync_with_stdio(0);
cin.tie(0);
#endif // ONLINE_JUDGE
cin >> n >> cs >> cf;
dp[0][0] = 1;
for(int i = 1; i < n; i++){
if(i == cs ||i== cf){
for(int j = 0; j < i; j++)
add(dp[i][j], dp[i-1][j]);
for(int j = 0; j < i; j++)
add(dp[i][j-1], dp[i-1][j] * 1ll * j % mod);
} else {
for(int j = 0; j < i; j++){
if(j >= 2)
add(dp[i][j-1], dp[i-1][j] * 1ll * j % mod * 1ll * (j-1) % mod);
if(i >= cs)
add(dp[i][j-1],dp[i-1][j] * 1ll * j % mod);
if(i >= cf)
add(dp[i][j-1],dp[i-1][j] * 1ll * j % mod);
add(dp[i][j+1], dp[i-1][j]);
}
}
}
cout << dp[n-1][0] << '\n';
return 0;
}
