#include<stdio.h>
#include<math.h>
int m,v[10000],i,k,ok=1,contor,j;
FILE *in=fopen("pairs.in","rt"),*out=fopen("pairs.out","wt");

int main()
{
	fscanf(in,"%d",&m);
	for(i=1;i<=m;i++)
	{
		fscanf(in,"%d",&v[i]);
		if(v[i]==v[i-1])
			ok=0;
	}
	if(ok==1)
	for(i=1;i<m;i++)
		for(k=i+1;k<=m;k++)
			if(v[i]!=v[k])
				if(v[i]<v[k])
				{
					for(j=2;j<=v[i];j++)
						if(v[i]%j==v[k]%j)
						 {
							contor++;
							break;
						 }
				}
				else
					for(j=1;j<=v[k];j++)
						if(v[i]%j!=v[k]%j)
						{
							contor++;
							break;
						}
	fprintf(out,"%d",contor);
	return 0;
}