def distance(x,y)
    2.times.inject(0) {|s, a| s + (x[a] - y[a]) ** 2 }
end

n = gets.to_i
coins = n.times.map {
    gets.split.map(&:to_i)
}

seat = coins.inject([]) {|s, i|
    unless s.any? {|j| distance(i,j) < 400 }
        s.push(i)
    end
    s
}

puts seat.size