#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#define deb(...) logger(#__VA_ARGS__, __VA_ARGS__)
template<typename ...Args>
void logger(string vars, Args&&... values) {
cerr<<vars<<" = ";
string delim="";
(...,(cerr<<delim<<values,delim=", "));
cerr<<"\n";
}
#else
#define deb(...) logger(#__VA_ARGS__, __VA_ARGS__)
template<typename ...Args>
void logger(string vars, Args&&... values) {}
#endif
#define pb push_back
#define sz(x) (int)(x.size())
typedef long long ll;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
template<typename T> inline void maxa(T& a,T b){a=max(a,b);}
template<typename T> inline void mina(T& a,T b){a=min(a,b);}
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int mxN=2e3+5; //make sure this is right
const int mod=1e9+7;
ll dp[mxN][mxN];
void add(ll &a, ll b){a=(a+b)%mod;}
/*
dp[i][j] -> at i, you have j components
create new component: dp[i][j] += dp[i-1][j-1]*j
merge 2 components: dp[i][j] += dp[i-1][j+1]*j
*/
int main(){
cin.sync_with_stdio(0);
cin.tie(0); cout.tie(0);
#ifdef LOCAL
freopen("input.txt","r",stdin);
freopen("output.txt","w",stdout);
#endif
int n,s,f; cin>>n>>s>>f;
dp[0][0]=1;
int cnt=0;
for(int i=1;i<=n;i++){
if(i==s || i==f) cnt++;
for(int j=0;j<=n;j++){
if(i==s || i==f){
if(j) add(dp[i][j],dp[i-1][j-1]);
if(j) add(dp[i][j],dp[i-1][j]);
} else{
if(j-cnt>0 && j) add(dp[i][j],dp[i-1][j-1]*(j-cnt));
add(dp[i][j],dp[i-1][j+1]*j);
}
// deb(i,j,dp[i][j]);
}
}
cout<<dp[n][1]<<"\n";
}
