4 cpp

#include <iostream>
#include <vector>
using namespace std;
int main() {
    int n, k=0;
    cin >> n;
    vector <long long> dp(n, 0);
    dp[0]=3;
    dp[1]=6;
    dp[2]=12;
    for (int i =3; i<n; i++) {
        dp[i]=dp[i-1]*2;
    }cout << dp[n-1];
    return 0;
}