#include"bits/stdc++.h"
using namespace std;
int main() {
	string s; cin >> s;
	string n = "0123456789";
	int k = 0;
	for (int i = 0; i < s.length(); i++) {
		for (int j = 0; j < 10; j++) {
			if (s[i] == n[j]) {
				k += j;
				break;
			}
		}
	}
	cout << k << endl;
}