#include<iostream>
using namespace std;
int main()
{
	int n;
	cin>>n;
	int max=0;
	int a,b,c;
	if(n<30)
	max=n/10;
	else if(n>=30&&n<50)
	max=4+(n-30)/10;
	else
	{
		a=n/50;
		b=(n-a*50)/30;
		c=(n-a*50-b*30)/10;
		max=a*7+b*4+c;
	}
	cout<<max;
	return 0;
}