#include <iostream>
#include <string>
#define REP(i,n) for(int i=0;i<(n);++i)
#define SORT(a) sort((a).begin(),(a).end())
#define PB push_back
using namespace std;

int main(){
  string S;
  cin >> S;
  int l = S.size();
  int r = 0;
  REP(i,l){
    char c = S[i];
    if(c >= '0' && c <= '9'){
      r += c - '0';
    }
  }
  cout << r << endl;
}