// #pragma GCC optimize("O3,unroll-loops")
// #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define vi vector<int>
#define vl vector<ll>
#define vii vector<pii>
#define db long double
#define vll vector<pll>
#define endl '\n'
#define all(x) x.begin(), x.end()
#define fastio ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define int long long
int res = 0, n, a, b;
vi path;
void dfs(int node, int cnt, int pre, vector<bool> used){
if(cnt == n - 1 and node == b){
res++;
// for(int i : path){
// cout << i << " ";
// }
// cout << endl;
return;
}
if(cnt == n - 1) return;
if(pre != 1){
for(int i = node + 1; i <= n; i++){
if(used[i]) continue;
path.push_back(i);
used[i] = true;
dfs(i, cnt + 1, 1, used);
path.pop_back();
used[i] = false;
}
}
if(pre != 0){
for(int i = node - 1; i >= 1; i--){
if(used[i]) continue;
path.push_back(i);
used[i] = true;
dfs(i, cnt + 1, 0, used);
path.pop_back();
used[i] = false;
}
}
}
void fmain(){
cin >> n >> a >> b;
vector<bool> usd(n + 1, false);
path.push_back(a);
usd[a] = true;
dfs(a, 0, -1, usd);
cout << res << " ";
path.clear();
}
signed main(){
int tmr = 1;
// cin >> tmr;
while(tmr--){
fmain();
}
// n = 6;
// for(int i = 1; i <= n; i++){
// for(int j = 1; j <= n; j++){
// if(i == j){
// cout << 0 << " ";
// continue;
// }
// a = i, b = j;
// fmain();
// }
// cout << endl;
// }
}
