#include <bits/stdc++.h>
#define int long long
using namespace std;
const int N = 2005;
int dp[N][N];
const int mod = 1e9+7;
void add(int &a,int b){
a = (a + b) % mod;
}
int32_t main() {
int n,st,en,diff=0;
cin >> n >> st >> en;
dp[1][1]=1;
if(st == 1 || en == 1) diff++;
for(int i = 1;i<=n;i++) {
for(int j = 1;j<=i;j++) {
if(i == st || i == en) {
// add new
if(i==1)continue;
add(dp[i+1][j+1],dp[i][j]);
// add to existing cmp
add(dp[i+1][j], dp[i][j]);
diff++;
} else {
// new cmp (use 3)
if(i+1!=st&&i+1!=en&&i+2!=st&&i+2!=en){
add(dp[i+3][j+1], dp[i][j] * 2 * (j - diff + 1));
}
// add to cmp
add(dp[i+1][j], dp[i][j] * (j - diff) * 2);
// merge cmp
if(j-1>=1)add(dp[i+1][j-1], dp[i][j] * (j-1));
}
// cerr << dp[i][j] << " ";
}
// cerr<<"\n";
}
cout << dp[n][1];
}
/*
no 3 can be increasing 2x or decreasing 2x
want to use the same update so force structure into the problme
*/
