#include <iostream>
#include <algorithm>
#include <string>
#include <vector>
#include <map>
#include <set>
#include <stdio.h>
#include <cstring>
#include <queue>
#include <stack>
#include <functional>
#include <math.h>
#include <iomanip>
using namespace std;
#define Would
#define you
const int INF = 999999999;
const int MOD = 1e9 + 7;

int digits(int n) {
	int ans = 0;
	while (n) {
		ans += n % 10;
		n /= 10;
	}
	return ans;
}

int ans;
int main() {
	string h;
	cin >> h;
	for (int i = 0; i < h.length(); ++i) {
		if (isdigit(h[i])) { ans += h[i] - '0'; }
	}
	cout << ans << endl;
}