#include using namespace std; struct Node { int x; }; Node queue[20]; int main() { queue[0].x = 1; int head = 0; int year; cin >> year; for (int i = 0; i < year;i++) { queue[i + 1].x = queue[i].x * 3; } int sum = 0; for (int i = 0; i < 20;i++) { if (queue[i].x == 0)break; sum += queue[i].x; } cout