#include <bits/stdc++.h>
using namespace std;
#define int long long
signed main(){
  int ans = 0;
  string S;
  cin>>S;
  for(int i=0;i<S.size();i++)if('0' <= S[i] && S[i] <= '9') ans += S[i]-'0';
  cout<<ans<<endl;
}