S=input()
Sl=list(S)
Si=[]
i=0
for i in range(len(Sl)):
    if Sl[i]=="9" or  Sl[i]=="8" or Sl[i]=="7" or  \
        Sl[i]=="6" or Sl [i]=="5" or  Sl[i]=="4" or \
        Sl[i]=="3" or  Sl[i]=="2" or  Sl[i]=="1" :
        Si.append(int(Sl[i]))
    i+=1
i=0
su=0
for i in range(len(Si)):
    if Si[i]<10:
        su+=Si[i]
print(su)