#include<fstream>
using namespace std;
class InputReader {
    public:
        InputReader() {}
        InputReader(const char *file_name) {
            input_file = fopen(file_name, "r");
            cursor = 0;
            fread(buffer, SIZE, 1, input_file);
        }
        inline InputReader &operator >>(int &n) {
            while(buffer[cursor] < '0' || buffer[cursor] > '9') {
                advance();
            }
            n = 0;
            while('0' <= buffer[cursor] && buffer[cursor] <= '9') {
                n = n * 10 + buffer[cursor] - '0';
                advance();
            }
            return *this;
        }
    private:
        FILE *input_file;
        static const int SIZE = 1 << 17;
        int cursor;
        char buffer[SIZE];
        inline void advance() {
            ++ cursor;
            if(cursor == SIZE) {
                cursor = 0;
                fread(buffer, SIZE, 1, input_file);
            }
        }
}f("pairs.in");
ofstream g("pairs.out");
int n,i,j,maxi,x,nr,d[1<<20];
long long sol;
bool v[1<<20];
int main()
{
    f>>n;
    sol=1LL*n*(n-1)/2;
    for(i=1;i<=n;++i)
    {
        f>>x;
        maxi=max(maxi,x);
        v[x]=1;
    }
    for(i=2;i<=maxi;++i)
    if(!d[i])
        for(j=i;j<=maxi;j+=i) d[j]++;
        for(i=2;i*i<=maxi;++i)
    for(j=i*i;j<=maxi;j+=i*i) d[j]=-1;
    for(i=2;i<=maxi;++i)
    if(d[i]!=-1)
    {
        nr=0;
        for(j=i;j<=maxi;j+=i)
        if(v[j]) ++nr;
        (d[i]&1)?sol-=1LL*nr*(nr-1)/2:sol+=1LL*nr*(nr-1)/2;
    }
    g<<sol<<'\n';
    return 0;
}