#include <stdio.h>
#define ll long long

bool v[1000001];

ll ciur[1000001];

int main()
{

    ll m=0,n=0,i,j,x,t,sol=0;

    freopen("pairs.in","r",stdin);
    freopen("pairs.out","w",stdout);

    scanf("%lld\n",&n);

    sol=n*(n-1)/2;

    for (i=1;i<=n;++i)
    {

        scanf("%lld",&x);

        v[x]=1;

        if (x>m)

            m=x;

    }

    for (i=2;i<=m;++i)
        if (!ciur[i])
            for (j=i;j<=m;j+=i)
                ++ciur[j];

    for (i=2;i*i<=m;++i)
        for (j=i*i;j<=m;j+=i*i)
            ciur[j]=-1;

    for (i=2;i<=m;++i)
        if (ciur[i]!=-1)
        {

            t=0;

            for (j=i,t=0;j<=m;j+=i)
                if (v[j])
                    ++t;

            sol-=((ciur[i]%2)*2-1)*t*(t-1)/2;//formula

        }

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

    return 0;

}