#include<stdio.h>
#include<iostream>
#include<string>

int main()
{
	int a,b;
	std::string tmp;
	a = 0;
	std::cin >> tmp;
	for (char c : tmp)
	{
		if (isdigit(c))
		{
			b = c - '0';
			a += b;
		}
	}

	std::cout << a;
	return 0;
}