ACM第1001题答案

ACM第1001题的答案，计算1到N的和。Input:Theinputwillconsistofaseriesofintegersn,oneintegerperline.Output:Foreachcase,outputSUM(n)inoneline,followedbyablankline.Youmayassumetheresultwillbeintherangeof32-bitsignedinteger.