#include<bits/stdc++.h>
using namespace std;
int main()
{
    int i,n,s=0,j;
    cin>>n;
    for(i=1;i<n;i++){
        for(j=i+1;j<=n;j++){
            if((i+j)%3==0||(i+j)%7==0)
                s++;
        }
    }
    cout<<s;
return 0;
}
/**************************************************************
	Problem: 1086
	User: lijinkai
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/