#include<bits/stdc++.h>
#define rep(i,a,n) for (int i = a;i < n;i++)
#define per(i,n,a) for (int i = n-1;i >= a;i--)
using namespace std;

int main() {
    string s; cin >> s;
    int sum = 0;
    rep(i,0,s.size()){
        if(s[i] >= '0' && s[i] <= '9')
            sum += s[i] - '0';
        }
    cout << sum << endl;
}