懒得说了上题解：

#include<bits/stdc++.h>
int main() {
	int n, p= 0; std::cin >> n;
	for (int a = 1; a <= n; ++a)
		for (int b = a; b <= n; ++b) {
			int c = sqrt(a * a + b * b);
			if (c > n || c * c != a * a + b * b) continue;
			++p;
		}
	std::cout << p;
	return 0;
}