1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
// clang-format off
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define ssize(x) int(x.size())
template<class A,class B>auto&operator<<(ostream&o,pair<A,B>p){return o<<'('<<p.first<<", "<<p.second<<')';}
template<typename T,typename = typename enable_if<!is_same<T,string>::value>::type>
auto operator<<(ostream&o,T x)->decltype(x.end(),o){o<<'{';int i=0;for(auto e:x)o<<(", ")+2*!i++<<e;return o<<'}';}
#ifdef DEBUG
#define debug(x...) cerr<<"["#x"]: ",[](auto...$){((cerr<<$<<"; "),...);}(x),cerr<<'\n'
#else
#define debug(...) {}
#endif
// clang-format on

int cnt[25000007];

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int n;
    cin >> n;
    set<int> squares;
    for (int i = 1; i <= n; i++)
        squares.insert(i * i);

    for (int i = 1; i <= n; i++)
    {
        for (int j = 1; j < i; j++)
        {
            cnt[i * i - j * j] += 1;
        }
    }

    int ans = 0;

    for (int a = 1; a < n; a++)
    {
        for (int b = a; a * a + b * b < n * n; b++)
        {
            ans += cnt[a * a + b * b];
        }
    }
    cout << ans << '\n';

    return 0;
}