#include <bits/stdc++.h>
#define rep(i,n)for(long long i=0;i<(n);i++)
using namespace std;
typedef long long ll;
const int MOD=1e9+7;
const int MAX = 1000000;
const int INF = 1e9;
const double pi=acos(-1);
using namespace std;

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;
  
  return 0;
}