program mn;
uses crt;
var a:array[1..100]of integer;
i,n,s:integer;
BEGIN
ClrScr;
Write('N:');
readln(n);randomize;
for i:=1 to n do
begin
a[i]:=random(30)-15;
Write(a[i],' ');
end;
writeln;
for i:=1 to n-1 do
if (a[i]>0)and(a[i+1]<0)or(a[i]<0)and(a[i+1]>0)
then inc(s);
Writeln(s);
readln;
END.