# -*- coding: utf-8 -*-
__author__ = 'yuuki'
#No.289 数字を全て足そう

S = raw_input()
N = ['1','2','3','4','5','6','7','8','9']
M = 0

for i in xrange(len(S)):
   for c in range(len(N)):
       if S[i] == N[c]:
           M += int(S[i])
           break
print M