A poor
man borrows a sum of N rupees from his neighbour. The neighbour is kind enough
not to impose any interest on the loan. The poor man agrees to re-pay the loan
by paying back either 1 rupee or 2 rupees to his neighbour. In how many distinct
ways can he repay the loan?
Input Format:
The first line will contain the value
of N which is the loan amount.
Output Format:
The first line will contain the
number of distinct ways in which the loan can be repaid.
Example Input/Output 1:
Input:
1
Output:
1
Example Input/Output 3:
Input:
5
Output:
8
Explanation:
The loan can be re-paid as
1,1,1,1,1 or
1,1,1,2 or
1,2,2 or
1,1,2,1 or
1,2,1,1 or
2,2,1 or
2,1,2 or
2,1,1,1
Solution:
n = int(input())
a = 0
b = 1
i = 0
while i<n:
c = a+b
a = b
b = c
i += 1
print(c)