Given that "Olga wrote all the natural numbers from 1 to k. Including 1 and k"
So Olga write k numbers.
lets take an example
if k = 10 , then natural numbers between 1 and 10 are 10 numbers that are 1 , 2 , 3 ,4 ,5 ,6 , 7 , 8 ,9 and 10.
Hence she write k numbers.
