Problem Description

WLD likes playing with codes.One day he is writing a function.Howerver,his computer breaks down because the function is too powerful.He is very sad.Can you help him?

The function:

int calc
{
  
  int res=0;
  
  for(int i=1;i<=n;i++)
    
    for(int j=1;j<=n;j++)
    
    {
      
      res+=gcd(a[i],a[j])*(gcd(a[i],a[j])-1);
      
      res%=10007;
    
    }
  
  return res;

}

 

Input

There are Multiple Cases.(At MOST 10)

For each case:

The first line contains an integer N(1≤N≤10000).

The next line contains N integers a1,a2,...,aN(1≤ai≤10000).

 

Output

For each case:

Print an integer,denoting what the function returns.

 

Sample Input

 

Sample Output

 

Source

#include<bits/stdc++.h>

using namespace std;

#define LL long long

#define pi (4*atan(1.0))

#define eps 1e-8

#define bug(x)  cout<<"bug"<<x<<endl;

const int N=1e4+,M=1e6+,inf=1e9+;

const LL INF=1e18+,mod=1e9+;

int cnt[N],sum[N];

int main()

{

    int n;

    while(~scanf("%d",&n))

    {

        memset(cnt,,sizeof(cnt));

        memset(sum,,sizeof(sum));

        for(int i=;i<=n;i++)

        {

            int x;

            scanf("%d",&x);

            cnt[x]++;

        }

        for(int i=;i<=;i++)

        {

            for(int j=i;j<=;j+=i)

                sum[i]+=cnt[j];

            sum[i]=sum[i]*sum[i];

        }

        LL ans=;

        for(int i=;i>=;i--)

        {

            for(int j=i+i;j<=;j+=i)

                sum[i]-=sum[j];

            //if(sum[i])cout<<i<<" "<<sum[i]<<endl;

            ans+=1LL*i*(i-)*sum[i];

            ans%=;

        }

        printf("%lld\n",ans);

    }

    return ;

}