#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9+7;
int n, sf, st, psd;
int dp[2005][2005]; //filled 1-i with j components
int main() {
psd = 0;
cin >> n >> sf >> st;
dp[0][0] = 1;
for(int i=1;i<=n;i++) {
if(i == sf || i == st) {
for(int k=1;k<=n;k++) dp[i][k] = dp[i-1][k];
for(int k=0;k<=n;k++) {
dp[i][k+1] += dp[i-1][k];
if(dp[i][k+1] >= mod) dp[i][k+1] -= mod;
}
psd++;
} else {
for(int k=0;k<=n;k++) { //make new compo
dp[i][k+1] += 1ll * dp[i-1][k] * max(0, k+1 - psd) % mod;
if(dp[i][k+1] >= mod) dp[i][k+1] -= mod;
}
for(int k=2;k<=n;k++) { //merge existing compo
dp[i][k-1] += 1ll * dp[i-1][k] * (k-1) % mod;
if(dp[i][k-1] >= mod) dp[i][k-1] -= mod;
}
}
}
cout << dp[n][1];
}
