values = []
number = 0
result = 0

# Builds the array. Ends when user press enter on an empty line.
while not number.to_s.empty?
number = gets.chomp
values << number.to_i
end

# Pops the last slot, the 'nil'.
values.pop

# The sum of the values.
values.each do |value|
result = result + value
end

puts result