#include<fstream>

using namespace std;

int n,a[1000],p;
int prime(int x,int y)
{
    while(x!=y)
    {
               if(x > y)
               x = x-y;
               if(y > x)
               y = y-x;
    }
    if(y == 1) return 1;
    else return 0;
}
int main()
{
    ifstream fin("pairs.in");
    ofstream fout("pairs.out");
int i,j;
fin>>n;
for(i = 1; i <= n; i++)
fin>>a[i];
for(i = 1; i <= n; i++)
{
      for(j = i+1; j <= n; j++)
            if(prime(a[i],a[j]) == 1)
            {
                                fout<<a[i]<<" "<<a[j]<<"\n";
                                p++;
            }
}
fout<<p;

fin.close();
fout.close();

}