sum = gets.to_i
kado = gets.to_s.split(" ")
matsu = kado[0]
matsu = kado[1]
matsu = kado[2]
ans = 0
for i in 4..sum do
   if (matsh[2] < matsu[1] and matsu[2] < mstsu[3]) or (matsu[2] > matsu[1] and matsu[2] > matsu[3])
      ans = ans + 1
   end
   matsu.shift
   matsu.push(matsu(i-1))
end