1149.Summing consecutive integer in python

This is the solution of the problem in python:

lista=input().split(" ")
count=len(lista)
A=int(lista[0])
for i in range(1,count+1):
    K=int(lista[i])
    if(K>0):
        N=int(lista[i])
        break
T=A+N
Sum=0
for j in range(A,T):
    Sum=Sum+j
print(Sum)