#include<stdio.h>
long int n,m[10000];

int prime (long int x, long int y)
    {
    long int d,i,r;
    d=x;
    i=y;
    while (i)
	  {
	  r=d%i;
	  d=i;
	  i=r;
	  }
    if (d==1)
       return 1;
    return 0;
    }

int main ()
{
long int i,j,nr=0;
FILE *f;
f=fopen("pairs.in","r");
fscanf(f,"%ld",&n);
for (i=1;i<=n;i++)
    fscanf(f,"%ld",&m[i]);
fclose(f);
f=fopen("pairs.out","w");
for (i=1;i<=n;i++)
    for (j=i+1;j<=n;j++)
	if (m[i]==1||m[j]==1)
	   ++nr;
	else
	   if (m[i]%2!=0&&m[j]%2!=0||m[i]%2!=0&&m[j]%2==0||m[i]%2==0&&m[j]%2!=0)
	      if (prime(m[i],m[j]))
		 ++nr;
fprintf(f,"%ld",nr);
fclose(f);
return 0;
}