#include<bits/stdc++.h>
using namespace std;
const int MX = 2002;
const int Mod = 1e9 + 7;
int add(int a, int b) {
a += b;
if(a>=Mod) a -= Mod;
return a;
}
int mul(int a, int b) {
return (a * 1LL * b) % Mod;
}
int n, cs, cf;
int dp[MX][MX/2][2][2];
int solve(int i, int j, bool ad1, bool ad2) {
if(i==n-1) return 1;
int &ret = dp[i][j][ad1][ad2];
if(ret!=-1) return ret;
if(i==cs || i==cf) return ret = solve(i+1, j, ad1, ad2);
ret = 0;
//new component
if(j+1<=(n+1)/2) ret = add(ret, mul(j-1, solve(i+1, j+1, ad1, ad2)));
//merge
if(j>2) ret = add(ret, mul(j-1, solve(i+1, j-1, ad1, ad2)));
//extend
if(!ad1 && i<cs) ret = add(ret, solve(i+1, j, 1, ad2));
if(!ad2 && i<cf) ret = add(ret, solve(i+1, j, ad1, 1));
return ret;
}
void PlayGround() {
cin>>n>>cs>>cf;
memset(dp, -1, sizeof dp);
cout<<solve(1, 2, 0, 0)<<'\n';
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(0);
PlayGround();
return 0;
}
