#include <bits/stdc++.h> #include <ext/pb_ds/assoc_container.hpp> #include <ext/pb_ds/tree_policy.hpp> using namespace __gnu_pbds; using namespace std; #ifdef LOCAL #include "debug.h" #else #define debug(...) 42 #endif #define ll long long #define ld long double #define pii pair<int,int> #define all(x) (x).begin(), (x).end() #define isz(x) (int)(x.size()) #define vi vector<int> #define vvi vector<vi> #define ost tree<pii, null_type, less<pii>, rb_tree_tag, tree_order_statistics_node_update> mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count()); const int sz = 205, inf = 1000000000; const ll mod = 1000000007, INF = 1000000000000000000; int dp[sz][sz][sz][2]; // 0 -> increasing // 1 -> decreasing void solve() { int n, cs, cf; cin >> n >> cs >> cf; memset(dp, 0, sizeof(dp)); dp[2][1][2][0] = 1; dp[2][2][1][1] = 1; for (int i = 3; i <= n; i++) { for (int s = 1; s <= i; s++) { for (int f = 1; f <= i; f++) { if (s == f) continue; for (int k = s; k < i; k++) dp[i][s][f][0] += dp[i-1][k][f - (f > s)][1]; for (int k = 1; k < s; k++) dp[i][s][f][1] += dp[i-1][k][f - (f > s)][0]; } } } cout << dp[n][cs][cf][0] + dp[n][cs][cf][1] << '\n'; } void precompute() {} signed main() { ios::sync_with_stdio(false); cin.tie(nullptr); #ifdef LOCAL freopen("err.log", "w", stderr); freopen("in.txt", "r", stdin); #endif precompute(); solve(); return 0; }