gets # 不要なので捨て
shuffles = gets.chomp.split.map{|str| str.to_i}
target = 1
shuffles.reverse.each {|tmp|
  if target == 1
    target = tmp
    next
  end
  if tmp < target
    next
  elsif tmp > target
    target -= 1
  else
    target = 1
  end
}
puts target