#include <iostream>
#include <string>
#include <vector>
#include <algorithm>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <cmath>
#include <cstdlib>
#include <sstream>
#include <cstdio>
#include <iterator>

#define N 1000
#define re(i,n) for(int i=0;i<(n);i++)
#define rep(i,a,b) for(int i=(a);i<(b);i++)
#define fe(i,n,f) for_each(i,n,f)
using namespace std;

typedef long long ll;

int main(void){
	string s;
	int k=0;
	cin>>s;
	re(i,s.size()) if('0'<=s[i]&&s[i]<='9') k+=s[i]-'0';
	cout<<k<<endl;
	return 0;
}