#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
typedef pair<int,int> P;
 
const int INF = 1e9;
const int mod = 1e9+7;
const double EPS = 1e-10;
const double PI = acos(-1.0);
 
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;
    return 0;
}