# import pypyjit
# pypyjit.set_param('max_unroll_recursion=-1')
from collections import *
from itertools import *
from functools import *
from heapq import *
import sys,math
input = sys.stdin.readline

S = list(input())[:-1]
S = [int(i) for i in S]
ans = 0
for s in S:
    if s==0:
        ans += 10
    else:
        ans += s
print(ans)