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

int main()
{
	string S;
	cin >> S;

	long long ans = 0;
	for( int i = 0; i < S.size(); i++ ) {
		if( isdigit( S[i] ) == false ) continue;
		ans += S[i] - '0';
	}

	cout << ans << endl;
}