#include <iostream>
#include <string>
using namespace std;

int main()
{
    string S;
    cin >> S;
    
    int ans = 0;
    
    for (int i = 0; i < S.length(); i++) {
        if (S[i] >= 'a' && S[i] <= 'z') continue;
        ans += S[i] - '0';
    }
    
    cout << ans << endl;
    
    return 0;
}