#include<iostream> using namespace std; int main(){ int kun ; cin >> kun; int sum = kun; int kong = kun; while(true){ kun = kong / 3; sum += kun; kong = kong % 3 + kun; if(kong < 3){ break; } } }

#include<iostream> using namespace std; int main(){ int n,all=0,last=0; cin>>n; all+=n; while(n+last>=3){ all+=n/3; last+=n%3+n/3; n=last; last=0; } cout<<all; return 0; }