#include <iostream>
#include <cstdlib>

int main()
{
    using namespace std;
    char input[10000];
    int result = 0;
    cin >> input;
    for (char& element:input){
        if (element == 0) break;
        if (isdigit(element)) result += element - 48;
    }
    cout << result << endl;
}