#include<bits/stdc++.h>
#define rep(i, x) for(ll i = 0; i < x; i++)
#define rep2(i, x) for(ll i = 1; i <= x; i++)
#define all(a) (a).begin(),(a).end()
using ll = long long;
using ld = long double;
const ll INF = 10000000000000000;
using namespace std;
signed main() {
	string s; cin >> s; ll cnt = 0;
	rep(i, s.size()) {
		if (48 <= (ll)s[i] && (ll)s[i] <= 57) { cnt += ((ll)s[i] - 48); }
	}
	cout << cnt << endl;
	return 0;
}