for 变量 in range(x):

   循环需要执行的代码

def main():

 sum = 0  # 定义变量做累加器

 n = int(input('n='))  #从键盘上输入累加的范围

 for x in range(n):  

  sum += (x + 1)

 print(sum)

 

if __name__ == '__main__':

 main()

def main():
  sum = 0
  n = int(input('n='))
  for x in range(n):
    sum += (x + 1)
  print(sum)
 
if __name__ == '__main__':
  main()