#include <bits/stdc++.h>
#define PB push_back
#define MP make_pair
#define REP(i,n) for (int i=0;i<(n);i++)
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define ALL(a) (a).begin(),(a).end()
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> P;
const int INF=1e9;
const int MOD=100000;
int B=1000000;
int main(){
      string s;
      cin>>s;
      int ans=0;
      REP(i,s.size()){
            if('0'<=s[i]&&s[i]<='9')ans+=(s[i]-'0');
      }
      cout<<ans<<endl;
}