#include <iostream>		//cin, cout
#include <vector>		//vector
#include <algorithm>	//sort,min,max,count
#include <string>		//string,getline, to_string

using namespace std;

int main() {

	string S;
	cin >> S;

	int ans = 0;

	for (unsigned int i = 0; i < S.length(); i++) {
		if ('0' <= S[i] && S[i] <= '9') {
			ans += S[i] - '0';
		}
	}

	cout << ans << endl;

	return 0;

}