a=input()
b=["0","1","2","3","4","5","6","7","8","9"]
num=[]

for i in range(len(a)):
    if a[i] in b:
        num.append(a[i])

#print(num)

for i in range(len(num)):
    num[i]=int(num[i])
    

result=sum(num)

print(result)