import sys

sys.setrecursionlimit(10 ** 6)
stdin = sys.stdin

ni = lambda: int(ns())
na = lambda: list(map(int, stdin.readline().split()))
ns = lambda: stdin.readline().strip()
nsa = lambda: list(stdin.readline().split())
mod = 10 * 7 + 7

S = ns()

num = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9'}
ans = 0

for s in S:
    if s in num:
        ans += int(s)

print(ans)