```
n = -2
while n <= 0:
print("Please enter a natural number i.e. whole number greater than zero ")
x=input('Enter a natural number : ')
n= int(x)
print(n)
print('The average of first ',n,'natural numbers = ',(n(n+1))/2*n )
```

here error is in last line saying that ‘int’ object is not callable