#include<fstream>
 long n,v[100001];
long prim(int a,int b){
while(a!=b)if(a>b)a=a-b;
	    else b=b-a;
	    return a;}

void main(){
ifstream f("pairs.in");
ofstream g("pairs.out");
long  nr,i,j;
nr=0;
f>>n;
for(i=1;i<=n;i++)f>>v[i];
f.close();
for(i=1;i<=n-1;i++)
for(j=i+1;j<=n;j++)if(prim(v[i],v[j])==1)nr++;
g<<nr;
g.close();return 0;}