#include <stdio.h>
#include <algorithm>
#include <deque>
using namespace std;
using ll = long long;

//289
int main() {
	int sum = 0;
	char s[10001];
	scanf("%s", s);

	for (int p = 0; s[p] != 0; p++)
		if ('1' <= s[p] && s[p] <= '9')
			sum += s[p] - '0';

	printf("%d\n", sum);
}