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
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define imie(x...) cerr << "[" #x "]: ", [](auto... $) {((cerr << $ << "; "), ...); }(x), cerr << '\n'
using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef long double ld;
const int mod=1e9+7;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;

int main()
{
    ios_base::sync_with_stdio(0); cin.tie(0);
    
    int n;
    cin >> n;
    int S = n * n - 1;
    vector<ll> cnt(S + 1, 0);
    for(int a = 1; a <= n; a++){
        ll a2 = a * a;
        for(int b = a; b <= n; b++){
            ll s = a2 + b * b;
            if(s > S) break;
            cnt[s]++;
        }
    }
    ll ans = 0;
    for(int h = 1; h <= n; h++){
        ll h2 = h * h;
        for(int d = h + 1; d <= n; d++){
            ll d2 = d * d;
            ll s = d2 - h2;
            if(s > S) continue;
            ans += cnt[s];
        }
    }
    
    cout << ans << "\n";
    return 0;
}