var v:array[1..10000] of longint;
var s,i,n,j:integer;      f:text;
function prim(x,y:longint): boolean;
begin
 while x<>y do
  if x>y then x:=x-y
         else y:=y-x;
 if x=1 then prim:=true   else prim:=false;
end;
begin
 s:=0;
 assign(f,'pairs.in'); reset(f);
 readln(f,n);
 for i:=1 to n do
  readln(f,v[i]);    close(f);
 for i:=1 to n do
  for j:=i to n do
   if prim(v[i],v[j])=true then s:=s+1;
 assign(f,'pairs.out'); rewrite(f);
 write(f,s); close(f);
end.