def main():
    s = input()
    num_s = []
    list_s = list(str(s))
    for i in range(len(list_s)):
        if print(type(list_s[i]) is int):
            num_s.append(int(list_s[i]))

    sum = 0
    for j in range(len(num_s)):
        sum += num_s[j]
    print(sum)


if __name__ == "__main__":
    main()