範例程式碼 uva580

//uva580
#include<iostream>

using namespace std;

int main(){

    int n;
    
    while (cin >> n && n){

        int U[31] = {0}, L[31] = {0};

        U[3] = 1;
        for(int i = 4 ; i <= n ; i++){
            U[i] = L[i-1] + (U[i-1] - L[i-3] + (1<<(i-4)));
            L[i] = U[i-1] + L[i-1];
        }

        cout << U[n] + L[n] << "\n";


    }


}