#include<bits/stdc++.h>
using namespace std;
int dp[1009][3];

int main(){
  string S;
  cin >> S;
  int ans=0;
  for(int i=0;i<S.size();i++){
    if('1'<=S[i] && S[i]<='9'){ans+=S[i]-'0';}
  }
  cout << ans << endl;
}