N = gets.to_i
A = gets.split.map(&:to_i)
MOD = 10 ** 9 + 7
min_a, max_a = A.minmax

if min_a == 0
  puts -1
  exit
end

if max_a >= 4
  puts MOD
  exit
end

res = 1

A.each do |a|
  res *= a.pow((1..a).inject(:*))

  if res > MOD
    puts MOD
    exit
  end
end

puts MOD % res