# include <iostream>
# include <algorithm>
# include <vector>
# include <string>
# include <set>
# include <map>
# include <cmath>
# include <iomanip>
# include <functional>
# include <utility>
# include <stack>
# include <queue>
# include <list>
using namespace std;
using LL = long long;
constexpr int MOD = 1000000000 + 7;
//足し算してオーバーフローで死なないように確認しようね
constexpr int INF = 1000000000;
const double PI = acos(-1);

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