#include <bits/stdc++.h>
using namespace std;
#define F first
#define S second
#define pb push_back
#define int long long
#define no cout << "No" << '\n'
#define yes cout << "Yes" << '\n'
#define all(v) v.begin(), v.end()
#define rall(v) v.rbegin(), v.rend()
#define inp(v) for (auto &a : v) cin >> a;
#define out(v) for (auto &a : v) cout << a << ' ';
void solve() {
int n, a, b;
cin >> n >> a >> b;
vector<int> vt(n);
for(int i = 1; i <= n; i++){
vt[i - 1] = i;
}
int mod = 1e9 + 7;
int ans = 0;
do {
bool ok = true;
for (int i = 1; i < n - 1; i++) {
if (!(vt[i] > vt[i - 1] and vt[i] > vt[i + 1] or vt[i] < vt[i - 1] and vt[i] < vt[i + 1])){
ok = false;
}
}
if (vt[0] != a or vt[n - 1] != b) {
ok = false;
}
if (ok) ans++;
}while(next_permutation(all(vt)));
cout << ans << '\n';
}
signed main() {
ios_base::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
int t = 1;
//cin >> t;
while(t--) solve();
}
