#include <iostream>
#include <fstream>
#include <cstdio>
#include <cmath>
#include <vector>
#include <string>
#include <set>
#include <map>
#include <queue>
#include <algorithm>
using namespace std;

#define REP(i,n) for(int i=0; i<n; i++)
#define FOR(i,a,b) for(int i=a; i<=b; i++)
#define FORR(i,a,b) for (int i=a; i>=b; i--)

typedef long long ll;

int main(void){
	string str;
	cin >> str;
	int ans = 0;
	REP(i,str.length()){
		if (str[i]>='0' && str[i]<='9')
			ans += str[i]-'0';
	}

	cout << ans << endl;

	return 0;
}