#include <math.h> #include #include <stdio.h> #include #include #include #include <string.h> #include using namespace std; #define LL long long const int N = 1e5 + 10; const int INF = 0x3f3f3f3f; int main() { int n , sum = 0 ,k = 0; cin >> n; sum = n; while(n >= 3) { sum +=n/3; n = n/3 +n%3; } cout<<sum<<endl; }