85

var n, i, b, ans : integer;
a:array[0..11] of integer;

begin
    read(n);

    for i:=0 to 11 do
        a[i]:=0;

    for i:=0 to n-1 do begin
        read(b);
        a[b mod 12]:=a[b mod 12]+1;
    end;

    ans:=0;
    for i:=0 to 11 do
        if((i<>6) and (i<>0)) then
            ans+=a[i]*a[12-i];

    write((ans div 2)+((a[0]*(a[0]-1)) div 2)+((a[6]*(a[6]-1)) div 2) );
end.