#include <bits/stdc++.h> using namespace std; // #pragma GCC optimize("Ofast") // #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,avx2,fma") // #pragma GCC optimize("unroll-loops") #define ll long long #define int128 __int128_t #define pii pair<int, int> #define int long long #define pb push_back #define F first #define S second #define all(v) (v).begin(), (v).end() #define rall(v) (v).begin(), (v).end() #define MOD 1000000007 #define INF (ll)1e18 #define RINF (ll) - 1e18 void cinv(vector<int> &a, int n) { for (int i = 0; i < n; i++) { cin >> a[i]; } } void coutv(vector<int> &a, int n) { for (int i = 0; i < n; i++) { cout << a[i] << " "; } } void solve() { int n, a, b; cin >> n >> a >> b; vector<int> c; for (int i = 1; i <= n; i++) { if (i != a && i != b) c.push_back(i); } int q = 0; do { bool g = true; for (int i = 0; i < c.size(); i++) { if(i==0){ if((c[i]>a && c[i]>c[i+1]) || (c[i]<a && c[i]<c[i+1])){ continue; } else{ g = false; } } else if(i==c.size()-1){ if((c[i]>b && c[i]>c[i-1]) || (c[i]<b && c[i]<c[i- 1])){ continue; } else{ g = false; } } else{ if((c[i]>c[i-1] && c[i]>c[i+1]) || (c[i]<c[i-1] && c[i]<c[i+1])){ continue; } else{ g = false; } } } if(g) q++; } while (next_permutation(c.begin(), c.end())); cout << q << endl; } signed main() { ios_base::sync_with_stdio(false); cin.tie(NULL); int t = 1; // cin >> t; while (t--) { solve(); } } // 5 2 3 // 2 // 1 - 2. 4 - 1. 5 - 2 // 1 - 2 4 - 0 5 - 2 // 1 - 2 4 - 1 5 - 2 // 3 // 32