def is_int(x):
    try:
        int(x)
    except ValueError:
        return False
    else:
        return True
    
S = input()
S_list = list(S)
S_length = len(S_list)
solution = int(0)
for i in range(S_length):
    if is_int(S_list[i]) == True:
        solution = solution + int(S_list[i])

print(solution)