How could I calculate the sum of 1 to n??

Question

def f(N):
N=0
try:
N=int(N)
except ValueError:
print('You did not enter a valid integer')
sys.exit(0)
if N<=0:
return 0
else:
y=0
x=1
while y<N:
y=y+x
x=x+1
print(N)

I don't know what's wrong with it....sad

Answer 1

just print
n(n+1)/2 //if n>=1 && n%1.0==0.0
else print "enter a natural number"
//don't know python 😕 , but u apply this to get better solution

Answer 2

I need to define f(n), and if n<0 return to 0 and raise an error if n is not a integar