n=gets.to_i
a=Array.new(n){gets.split.map(&:to_i)}
ary=[]
cnt=0
(0...n-1).each do |i|
  if ary.include?([ a[i+1][0] -a[i][0], a[i+1][1] -a[i][1] ])
    cnt+=1
  else
    ary<<[ a[i+1][0] -a[i][0], a[i+1][1] -a[i][1] ]
  end
end
p ary_num.uniq.inject(:+)-cnt+1
