Language: C++

/*
	watch me go
*/
#pragma GCC optimize("O3")
//#pragma comment(linker, "/stack:200000000")
#pragma GCC optimize("Ofast")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#include<bits/stdc++.h>
using namespace std;
#define int long long
//#define d long double
#define pii pair<int,int>
#define pb push_back
#define inf (int)1e18
#define init(x,a) memset(x,a,sizeof(x))
#define all(c) c.begin(),c.end()
int const mod=998244353;
int const mod1=1000000007;
int toint(const string &s) {stringstream ss; ss << s; int x; ss >> x; return x;}
string tostring ( int number ) {stringstream ss; ss << number; return ss.str();}
#define out(x) cout<<#x<<" = "<<" "<<x<<"\n";
#define trace1(x)                cerr<<#x<<": "<<x<<endl
#define trace2(x, y)             cerr<<#x<<": "<<x<<" | "<<#y<<": "<<y<<endl
#define trace3(x, y, z)          cerr<<#x<<":" <<x<<" | "<<#y<<": "<<y<<" | "<<#z<<": "<<z<<endl
 #define haha ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
// *** Using PBDS ***
// typedef tree<long long, null_type, less<long long>, rb_tree_tag, 
//              tree_order_statistics_node_update> 
//                 os; 
// *** Using PBDS ***
int modexp(int x, int n){
	if(n==0){
		return 1;
	}
	else if(n&1){
		return (modexp((x*x)%mod, n/2)%mod * x%mod)%mod;
	}
	else{
		return (modexp((x*x)%mod, n/2)%mod);
	}
}
 
int modinv(int n)
{
	return modexp(n,mod-2);
}
bool compare(pii a,pii b)
{
    return a.first<b.first;
}

struct custom_hash {
    static uint64_t splitmix64(uint64_t x) {
        // http://xorshift.di.unimi.it/splitmix64.c
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }

    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};



signed main() 
{
    haha
    int n;
    cin>>n;
    int s=0;
    int t=pow(n,3);
    int c=0;
    for(int i=2;i<=n;i++)
    {
        for(int j=i;j<=n;j+=i)
        {
            for(int z=i;z<=n;z+=i)
            {
                int l=__gcd(j,z);
                for(int h=i;h<=n;h+=i)
                {
                    if(__gcd(l,h)==i)
                    {
                    c++;
                    s+=i;
                    }
                    
                }
            }
        }
       // cout<<s<<endl;
    }
   // cout<<s<<endl;
    cout<<t-c+s;
    
   
}
    
    

Compiler output:
In file included from /usr/include/c++/14/string:43,
                 from /usr/include/c++/14/bitset:52,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:52,
                 from a.cc:8:
/usr/include/c++/14/bits/allocator.h: In destructor 'std::__cxx11::basic_string<char>::_Alloc_hider::~_Alloc_hider()':
/usr/include/c++/14/bits/allocator.h:182:7: error: inlining failed in call to 'always_inline' 'std::allocator< <template-parameter-1-1> >::~allocator() noexcept [with _Tp = char]': target specific option mismatch
  182 |       ~allocator() _GLIBCXX_NOTHROW { }
      |       ^
In file included from /usr/include/c++/14/string:54:
/usr/include/c++/14/bits/basic_string.h:186:14: note: called from here
  186 |       struct _Alloc_hider : allocator_type // TODO check __is_final
      |              ^~~~~~~~~~~~