#include <bits/stdc++.h>
#include<atcoder/all>
using namespace std;
using namespace atcoder;

using ll=long long;
ll mod=1000000007;
ll INF=1LL<<60;

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