摘要：
Problem DescriptionIn this problem, your task is to calculate SUM(n) = 1 + 2 + 3 + ... + n.InputThe input will consist of a series of integers n, one integer per lineOutputFor each case, output SUM(n) in one line, followed by a blank line. You may assume the result will be in the range of 32-bit sig 阅读全文
