#include <bits/stdc++.h>
using namespace std;
#define rep(i,n) for(int i=0;i<(int)(n);i++)
template<class T> inline bool chmax(T&a,T b){if(a<b){a=b;return 1;}return 0;}
template<class T> inline bool chmin(T&a,T b){if(a>b){a=b;return 1;}return 0;}
using ll = long long;

string s;

int main () {
  cin.tie(0); ios::sync_with_stdio(false); 

  cin >> s;
  int ans=0;
  for(auto c : s)if(isdigit(c)) ans+=c-'0';
  cout << ans << endl;
}