import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.lang.StringBuilder;
public class Main {
	public static void main(String[] args) throws Exception{
		BufferedReader sc = new BufferedReader(new InputStreamReader(System.in));
		StringBuilder sb = new StringBuilder();
		int t = 0;
		do{
			String[] st = sc.readLine().split("");
			int[] x = new int[st.length];
			if(st[0].equals("0"))
				break;
			for(int i = 0;i < st.length;i++){
				x[i] = Integer.parseInt(st[i]);
			}
			for(int n:x){
				t += n;
			}
			sb.append(t).append("\n");
			t = 0;
		}while(true);
		System.out.print(sb);
	}
}
/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