#include <bits/stdc++.h>
#define ll long long
#define int ll
#define ld long double
#define all(v) v.begin(),v.end()
#define rall(v) v.rbegin(),v.rend()
#define vi vector<int>
#define vvi vector<vi>
#define vvv vector<vvi>
#define vpi vector<pair<int,int>>
#define sz(v) (int)v.size()
#define pb push_back
#define ii pair<int,int>
#define F first
#define S second
using namespace std;
const int mod = 1e9+7, N = 100+5 ,M=1005;
const ll inf = 1e18;
int dx[] = {0, 0, 1, -1, 1, 1, -1, -1};
int dy[] = {-1, 1, 0, 0, 1, -1, 1, -1};
int n,s,e;
vvi dp;
int calc(int i,int c){
if(i>n) return c==1;
int &ret=dp[i][c];
if(~ret) return ret;
ret=0;
if(i==s||i==e){
// new comp
ret+=calc(i+1,c+1)%mod;
// extend comp
if(c)
ret+=calc(i+1,c)%mod;
ret%=mod;
}
else{
// new comp
ret+=(c+1-(i>s)-(i>e))* calc(i+1,c+1)%mod;
// combine 2
if(c>=2)
ret+=(c-1)* calc(i+1,c-1)%mod;
ret%=mod;
}
return ret;
}
void here_we_go_again() {
cin>>n>>s>>e;
dp.assign(n+5,vi(n+5,-1));
cout<<calc(1,0);
}
int32_t main() {
ios_base::sync_with_stdio(false);
cin.tie(0), cout.tie(0);
int tc = 1;
// cin >> tc;
for(int i=1;i<=tc;++i) {
// cout<<"Case #"<<i<<": ";
here_we_go_again();
}
return 0;
}
