simple_array_sum.rb

#!/bin/ruby

def simpleArraySum(n, ar)
   sum = 0
    ar.each do |num|
        sum += num
    end
    sum
end

n = gets.strip.to_i
ar = gets.strip
ar = ar.split(' ').map(&:to_i)
result = simpleArraySum(n, ar)
puts result;