n = gets.chomp.to_i

a_array = []
n.times {
  a_vec = gets.chomp.split
  a_array << a_vec
}

count = 0
number = 0
n.times {|col|
  is_exist = true
  n.times {|row|
    line = a_array[row][col]
    is_exist = false if not (line == "nyanpass" or line == '-')
  }
  if is_exist
    count += 1
    number = col + 1
  end
}

p (count == 1) ? number : -1