Takahashi has two positive integers A and B.

It is known that A plus B equals N. Find the minimum possible value of "the sum of the digits of A" plus "the sum of the digits of B" (in base 10).

Constraints

* 2 ≤ N ≤ 10^5
* N is an integer.

Input

Input is given from Standard Input in the following format:


N


Output

Print the minimum possible value of "the sum of the digits of A" plus "the sum of the digits of B".

Examples

Input

15


Output

6


Input

100000


Output

10
N=input()

ans=float("inf")

for A in range(1,N):
	B=N-A
	A2=list(str(A))
	B2=list(str(B))
	ans=min( ans, sum( map(int,A2) )+ sum( map(int,B2) ) )

print ans