import java.io.BufferedReader;
import java.io.InputStreamReader;

public class Main {

	public static void main(String[] args) throws Exception {
        // TODO ?????????????????????????????????????????????
        
        
        try (BufferedReader br = new BufferedReader(new InputStreamReader(System.in))) {
            String line;
            int sum=0;
            while ((line = br.readLine()) != null) {
            	if(line.equals("0"))break;
            	sum=0;
            	for(int i=0;i<line.length();i++){
            		sum+=Integer.parseInt(line.substring(i, i+1));
            	}
            	System.out.println(sum);
            }
        }
    }

}
/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz