#include<iostream>
#include<algorithm>
using namespace std;
using lint=int64_t;

int main()
{
	string S;

	cin >> S;

	int ans=0;
	for(auto& i:S)
	{
		if('0'<=i && i<='9')
			ans+=(i-'0');
	}

	cout << ans << endl;
	return 0;
}