#include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;
int a,b,c,c2,n,ans;
int f(int x) { return x*x; }
int main()
{
	scanf("%d",&n);
	for (size_t i = 0; ; i++)
	{
		/* code */
		a++; b++;
		c2=f(a)+f(b);
		c=sqrt(c2);
		if (c>n)
		{
			/* code */
			break;
		}
		ans++;
	}
	
	printf("%d",ans);
	return 0;
}