#include<bits/stdc++.h>
using namespace std;

int main()
{
    string S;cin>>S;
    int count=0;
    for(int i=0;i<S.size();i++)
    {
        
        if(S[i]=='1')
        {
            count+=1;
        }
        if(S[i]=='2')
        {
            count+=2;
        }
        if(S[i]=='3')
        {
            count+=3;
        }
        if(S[i]=='4')
        {
            count+=4;
        }
        if(S[i]=='5')
        {
            count+=5;
        }
        if(S[i]=='6')
        {
            count+=6;
        }
        if(S[i]=='7')
        {
            count+=7;
        }
        if(S[i]=='8')
        {
            count+=8;
        }
        if(S[i]=='9')
        {
            count+=9;
        }
    }
    cout<<count<<endl;
}