#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
#define FOR(i,a,b) for(int i = (a) , _b = (b); i <= _b; ++i)
#define MASK(x) ((LL)(1)<<(x))
#define BIT(mask , x) (((mask)>>(x))&(1))
template<class X , class Y>
bool maximize(X &x , Y y){
if (x<y) return x=y,true; else return false;
}
template<class X,class Y>
bool minimize(X &x, Y y){
if (x>y) return x=y,true; else return false;
}
template<class T>
void compress(vector<T>&data){
sort(data.begin() , data.end()) ;
data.resize(unique(data.begin() , data.end()) - data.begin());
return;
}
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
int Rand(int l,int r){
return uniform_int_distribution<int>(l,r)(rng);
}
const int N = (int)2000;
const int MOD = (int)1e9+7;
int add(int a,int b){
return a + b >= MOD ?a + b - MOD : a + b;
}
int mul(int a,int b){
return (LL)a*b % MOD;
}
int start , finish , n;
int dp[N+2][N+2][2][2][2] = {};
int main(){
ios::sync_with_stdio(false);
cin.tie(0) ; cout.tie(0);
#define name "main"
if (fopen(name".inp","r")){
freopen(name".inp","r",stdin);
freopen(name".out","w",stdout);
}
cin >> n >> start >> finish;
dp[0][0][0][0][0] = 1;
FOR(i,0,n-1){
FOR(cur_comp , 0 , i) FOR(have_start , 0 , 1) FOR(have_end , 0 , 1) {
bool nxt_start = have_start | (i + 1 == start);
bool nxt_end = have_end | (i + 1 == finish);
//... create a new component
int &xx = dp[i+1][cur_comp+1][nxt_start][nxt_end][0];
xx = add(xx , dp[i][cur_comp][have_start][have_end][0]);
//... insert start and finish positions
int &x1 = dp[i+1][cur_comp][nxt_start][nxt_end][0];
int &x2 = dp[i+1][cur_comp][nxt_start][nxt_end][1];
LL tt = dp[i][cur_comp][have_start][have_end][0];
if (i + 1 == start && cur_comp == 1 && have_end){
x2 = add(x2 , tt);
}
else if (i + 1 == finish && cur_comp == 1 && have_start){
x2 = add(x2 , tt);
}
if (i + 1 == start){
x1 = add(x1 , tt * (cur_comp - have_end) % MOD);
}
if (i + 1 == finish){
x1 = add(x1 , tt * (cur_comp - have_start) % MOD);
}
//... merging two components together
if (cur_comp > 1 && i + 1 != start && i + 1 != finish){
int rest_comp = cur_comp - have_start - have_end;
LL t = dp[i][cur_comp][have_start][have_end][0];
int &t1 = dp[i+1][cur_comp-1][have_start][have_end][0];
int &t2 = dp[i+1][cur_comp-1][have_start][have_end][1];
t1 = add(t1 , (LL)t * rest_comp * (rest_comp - 1) % MOD);
if (have_start) {
t1 = add(t1 , (LL)t * rest_comp % MOD);
}
if (have_end){
t1 = add(t1 , (LL)t * rest_comp % MOD);
}
if (have_start && have_end && cur_comp == 2) {
t2 = add(t2 , t);
}
}
}
}
cout<<dp[n][1][1][1][1];
}
