N = STDIN.gets.to_i
A = STDIN.read.strip.split.map(&:to_i)

if !(2 .. 500000).include? N
    STDERR.puts "invalid N"
    exit 1
end

if N != A.size
    STDERR.puts "invalid A size"
    exit 1
end

if !A.all?{|x| (0 ... (2 ** 63)).include? x}
    STDERR.puts "Invalid A value"
    exit 1
end

sum = A.inject(:+)

if !(0 ... (2 ** 63)).include? sum
    STDERR.puts "Invalid sum"
    exit 1
end

puts sum