#include<iostream>
#include<sstream>
#include<string>
#include<ctype.h>

int main(){
    std::string in;
    std::cin >> in;
    int sum=0;
    for(char c:in){
        if(isdigit(c)){
            int t = c-'0';
            sum+=t;
        }
    }
    std::cout << sum << std::endl;
}