Eratostene6

#include <fstream>
using namespace std;

int main()
{
    int n;
    ifstream f("eratostene6.in");
    f>>n;
    int a[n+1];
    for(int i=1;i<=n;++i)
        f>>a[i];
    f.close();
    int j;
    long long cnt=0;
    for(int i=1;i<=n;++i)
    {
        j=i+i;
        while(j<=n)
        {
            if(a[i])
            {
                if(a[j]%a[i]==0)
                    ++cnt;
            }
            else
                if(a[i]==0&&a[j]==0)
                	++cnt;
            j+=i;
        }
    }
    ofstream g("eratostene6.out");
    g<<cnt;
    g.close();
    return 0;
}