damn

var
a:array[1..40] of integer;
i,j,k,n,a1,n5,a2:integer;
begin
readln(n);
readln(a1);
n5:=0;
For i:=2 to n do begin
If (a1 mod 10 <>5) then inc(n5);

readln(a2);
If (a2 mod 10 <>5) then k:=k+n5;

a1:=a2;
if n mod 2=0 then
j:=(n div 2)*(n-1)
else j:=(n div 2)*n;
end;

writeln(j-k);

end.