#22681: 嗯...a!!!!!!
20071124
(204-25范育綸)
#include<iostream>
using namespace std;
int main()
{
int a;
while(cin>>a)
{cout<<(a+2)/3<<endl;
}
}
#include<iostream>
using namespace std;
int main()
{
int a;
while(cin>>a)
{cout<<(a+2)/3<<endl;
}
}