#include <bits/stdc++.h> #include <string.h> using namespace std; int dfs(int n) //几号点 { if(n < 0) return 0; if(n == 0) return 1; int ans = 0; for(int i = 1; i <= n; ++i) ans += dfs(n - i); return ans; } long long dp[55]; int main() { int n; cin >> n; //cout << dfs(n) << endl; dp[0] = 1; for(int i = 1; i <= n; ++i) { for(int j = 1; j <= i; ++j) { dp[i] += dp[i - j]; } } cout << dp[n] << endl; return 0; }