#include <iostream>
#include <string>
using namespace std;
int main()
{
	string strA = "";
	cin >> strA;
	int iSum = 0;
	for (int iI = 0; iI < strA.size(); ++iI) {
		char c = strA.at(iI);
		if (c >= '0' && c<= '9') {
			iSum += (c-'0');
		}
	}
	cout << iSum << endl;
	return 0;
}