#include <bits/stdc++.h>
#define rep(i,a,b) for(int i = (a); i < (b); i++)
#define all(A) (A).begin(),(A).end()
#define MOD 1000000007
using namespace std;
using ll = long long;
using Graph = vector<vector<int>>;

int main() {
	string s; cin >> s;
	int ans = 0;
	rep(i,0,(int)s.size()){
		if(isdigit(s[i])) ans += s[i]-'0';
	}
	cout << ans;
}