#include <iostream>
#include <ctype.h>
using namespace std;

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