平常水题 - CodeForces - 304A

In mathematics, the Pythagorean theorem — is a relation in Euclidean geometry among the three sides of a right-angled triangle. In terms of areas, it states:

In any right-angled triangle, the area of the square whose side is the hypotenuse (the side opposite the right angle) is equal to the sum of the areas of the squares whose sides are the two legs (the two sides that meet at a right angle).

The theorem can be written as an equation relating the lengths of the sides a, b and c, often called the Pythagorean equation:

a2 + b2 = c2

where c represents the length of the hypotenuse, and a and b represent the lengths of the other two sides.

Given n, your task is to count how many right-angled triangles with side-lengths a, b and c that satisfied an inequality 1 ≤ a ≤ b ≤ c ≤ n.

Input

The only line contains one integer n (1 ≤ n ≤ 104) as we mentioned above.

Output

Print a single integer — the answer to the problem.

Example

Input

5

Output

1

Input

74

Output
35

题意：在1~n的数中，选3个数能组成多少个三直角三角形。

#include<bits/stdc++.h>
using namespace std;

int main(){
long long n,ans = 0;
cin>>n;
for(int i = n;i >= 5;i--)
for(int j = i - 1;j * j >= (i * i) / 2;j--){//最主要是这一部，降低复杂度。
int k = sqrt(i * i - j * j);
if(k * k + j * j == i * i)
ans++;
}
cout<<ans;
}