S = input()

count = 0
for i in range(len(S)):
    if S[i] == "0" or S[i] == "1" or \
       S[i] == "2" or S[i] == "3" or \
       S[i] == "4" or S[i] == "5" or \
       S[i] == "6" or S[i] == "7" or \
       S[i] == "8" or S[i] == "9":
        count += int(S[i])

print(count)