S = str(input())

S_box = []

for i in range(len(S)):
    S_box.append(S[i:i+1])

num_box = []
for i in range(len(S_box)):
    try:
        num_box.append(int(S_box[i]))
    except:
        continue

total_num = 0
for i in num_box:
    total_num += i

print(total_num)