#include <bits/stdc++.h>
#define speed ios_base::sync_with_stdio(0); cin.tie(0)
#define all(x) (x).begin(),(x).end()
#define F first
#define S second
//#pragma GCC optimize("O3,unroll-loops")
//#pragma GCC target("avx,avx2")
//#pragma GCC target("popcnt")
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef double db;
typedef long double ldb;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
const ll MAX=2e5+10,P=1e9+7;
const ll INF=0x3f3f3f3f,oo=0x3f3f3f3f3f3f3f3f;
const ldb eps=1e-6;
const ldb PI=acos(-1.0);
const int dir[4][2]={{0,1},{0,-1},{1,0},{-1,0}};
template<typename T>
using vvector = vector<vector<T>>;
int main() {
speed;
ll n,s,t;
cin>>n>>s>>t;
vvector<ll> dp(n+1,vector<ll>(n+1));
dp[1][1]=1;
for (int i=2;i<=n;i++) {
for (int j=1;j<=i;j++) {
if (i==s or i==t) dp[i][j]=dp[i-1][j-1]+dp[i-1][j];
else {
dp[i][j]=(j-(i>s)-(i>t))*dp[i-1][j-1]%P+j*dp[i-1][j+1]%P;
}
dp[i][j]%=P;
}
}
cout<<dp[n][1]<<"\n";
return 0;
}
