#include"bits/stdc++.h"
using namespace std;
using ll = long long;
using ld = long double;
#define rep(i,m,n) for(ll i=(ll)m;i<(ll)n;i++)
#define Endl endl
#define pr(i,j) make_pair(i,j) 
const ll mod = 998244353;
const ll inf = 5e18;
const ld pi = 3.14159265358979;
int main() {
	string s;
	cin >> s;
	ll ans = 0;
	rep(i, 0, s.length()) {
		if ('0' <= s[i] && s[i] <= '9') {
			ans += s[i] - '0';
		}
	}
	cout << ans << endl;
}