#include <iostream>
#include <string>
using namespace std;

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