import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class Main {
  static InputReader in;
  static PrintWriter out;

  static class Solution {
    void solve() throws IOException {
      while (true) {
        String x = in.next();
        if (x.equals("0")) {
          break;
        }
        
        long sum = 0;
        
        for (int i = 0; i < x.length(); i++) {          
          sum += Integer.parseInt(x.substring(i, i+1));
        }
       
       out.println(sum);
      }
      
//      End solve()
    }
//    End Solution
}

  public static void main(String[] args) throws IOException {
    in = new InputReader(System.in);
    out = new PrintWriter(System.out);
    Solution solver = new Solution();
    solver.solve();
    out.close();
}

  static class InputReader {
    public BufferedReader br;
    public StringTokenizer st;

    public InputReader(InputStream stream) {
      br = new BufferedReader(new InputStreamReader(stream));
    }

    public int nextInt() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Integer.parseInt(st.nextToken());
    }

    public long nextLong() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Long.parseLong(st.nextToken());
    }

    public String next() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return st.nextToken();
    }

    public double nextDouble() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Double.parseDouble(st.nextToken());
    }


  }

} import java.io.BufferedReader; BufferedReader java.io import java.io.IOException; IOException java.io import java.io.InputStream; InputStream java.io import java.io.InputStreamReader; InputStreamReader java.io import java.io.PrintWriter; PrintWriter java.io import java.util.StringTokenizer; StringTokenizer java.util public class Main {
  static InputReader in;
  static PrintWriter out;

  static class Solution {
    void solve() throws IOException {
      while (true) {
        String x = in.next();
        if (x.equals("0")) {
          break;
        }
        
        long sum = 0;
        
        for (int i = 0; i < x.length(); i++) {          
          sum += Integer.parseInt(x.substring(i, i+1));
        }
       
       out.println(sum);
      }
      
//      End solve()
    }
//    End Solution
}

  public static void main(String[] args) throws IOException {
    in = new InputReader(System.in);
    out = new PrintWriter(System.out);
    Solution solver = new Solution();
    solver.solve();
    out.close();
}

  static class InputReader {
    public BufferedReader br;
    public StringTokenizer st;

    public InputReader(InputStream stream) {
      br = new BufferedReader(new InputStreamReader(stream));
    }

    public int nextInt() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Integer.parseInt(st.nextToken());
    }

    public long nextLong() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Long.parseLong(st.nextToken());
    }

    public String next() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return st.nextToken();
    }

    public double nextDouble() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Double.parseDouble(st.nextToken());
    }


  }

} Main static InputReader in; in static PrintWriter out; out public static void main(String[] args) throws IOException {
    in = new InputReader(System.in);
    out = new PrintWriter(System.out);
    Solution solver = new Solution();
    solver.solve();
    out.close();
} main {
    in = new InputReader(System.in);
    out = new PrintWriter(System.out);
    Solution solver = new Solution();
    solver.solve();
    out.close();
} in = new InputReader(System.in) in new InputReader(System.in) out = new PrintWriter(System.out) out new PrintWriter(System.out) Solution solver = new Solution(); solver new Solution() solver.solve() solver.solve solver out.close() out.close out String[] args args static class Solution {
    void solve() throws IOException {
      while (true) {
        String x = in.next();
        if (x.equals("0")) {
          break;
        }
        
        long sum = 0;
        
        for (int i = 0; i < x.length(); i++) {          
          sum += Integer.parseInt(x.substring(i, i+1));
        }
       
       out.println(sum);
      }
      
//      End solve()
    }
//    End Solution
} Solution void solve() throws IOException {
      while (true) {
        String x = in.next();
        if (x.equals("0")) {
          break;
        }
        
        long sum = 0;
        
        for (int i = 0; i < x.length(); i++) {          
          sum += Integer.parseInt(x.substring(i, i+1));
        }
       
       out.println(sum);
      }
      
//      End solve()
    } solve {
      while (true) {
        String x = in.next();
        if (x.equals("0")) {
          break;
        }
        
        long sum = 0;
        
        for (int i = 0; i < x.length(); i++) {          
          sum += Integer.parseInt(x.substring(i, i+1));
        }
       
       out.println(sum);
      }
      
//      End solve()
    } while (true) {
        String x = in.next();
        if (x.equals("0")) {
          break;
        }
        
        long sum = 0;
        
        for (int i = 0; i < x.length(); i++) {          
          sum += Integer.parseInt(x.substring(i, i+1));
        }
       
       out.println(sum);
      } true {
        String x = in.next();
        if (x.equals("0")) {
          break;
        }
        
        long sum = 0;
        
        for (int i = 0; i < x.length(); i++) {          
          sum += Integer.parseInt(x.substring(i, i+1));
        }
       
       out.println(sum);
      } String x = in.next(); x in.next() in.next in if (x.equals("0")) {
          break;
        } x.equals("0") x.equals x "0" {
          break;
        } break; long sum = 0; sum 0 for (int i = 0; i < x.length(); i++) {          
          sum += Integer.parseInt(x.substring(i, i+1));
        } int i = 0; int i = 0; i 0 i < x.length() i x.length() x.length x i++ i++ i {          
          sum += Integer.parseInt(x.substring(i, i+1));
        } {          
          sum += Integer.parseInt(x.substring(i, i+1));
        } sum += Integer.parseInt(x.substring(i, i+1)) sum Integer.parseInt(x.substring(i, i+1)) Integer.parseInt Integer x.substring(i, i+1) x.substring x i i+1 i 1 out.println(sum) out.println out sum static class InputReader {
    public BufferedReader br;
    public StringTokenizer st;

    public InputReader(InputStream stream) {
      br = new BufferedReader(new InputStreamReader(stream));
    }

    public int nextInt() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Integer.parseInt(st.nextToken());
    }

    public long nextLong() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Long.parseLong(st.nextToken());
    }

    public String next() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return st.nextToken();
    }

    public double nextDouble() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Double.parseDouble(st.nextToken());
    }


  } InputReader public BufferedReader br; br public StringTokenizer st; st public InputReader(InputStream stream) {
      br = new BufferedReader(new InputStreamReader(stream));
    } InputReader {
      br = new BufferedReader(new InputStreamReader(stream));
    } br = new BufferedReader(new InputStreamReader(stream)) br new BufferedReader(new InputStreamReader(stream)) InputStream stream stream public int nextInt() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Integer.parseInt(st.nextToken());
    } nextInt {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Integer.parseInt(st.nextToken());
    } while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      } st == null || !st.hasMoreTokens() st == null st null !st.hasMoreTokens() st.hasMoreTokens() st.hasMoreTokens st {
        st = new StringTokenizer(br.readLine());
      } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return Integer.parseInt(st.nextToken()); Integer.parseInt(st.nextToken()) Integer.parseInt Integer st.nextToken() st.nextToken st public long nextLong() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Long.parseLong(st.nextToken());
    } nextLong {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Long.parseLong(st.nextToken());
    } while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      } st == null || !st.hasMoreTokens() st == null st null !st.hasMoreTokens() st.hasMoreTokens() st.hasMoreTokens st {
        st = new StringTokenizer(br.readLine());
      } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return Long.parseLong(st.nextToken()); Long.parseLong(st.nextToken()) Long.parseLong Long st.nextToken() st.nextToken st public String next() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return st.nextToken();
    } next {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return st.nextToken();
    } while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      } st == null || !st.hasMoreTokens() st == null st null !st.hasMoreTokens() st.hasMoreTokens() st.hasMoreTokens st {
        st = new StringTokenizer(br.readLine());
      } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return st.nextToken(); st.nextToken() st.nextToken st public double nextDouble() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Double.parseDouble(st.nextToken());
    } nextDouble {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Double.parseDouble(st.nextToken());
    } while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      } st == null || !st.hasMoreTokens() st == null st null !st.hasMoreTokens() st.hasMoreTokens() st.hasMoreTokens st {
        st = new StringTokenizer(br.readLine());
      } st = new StringTokenizer(br.readLine()) st new StringTokenizer(br.readLine()) return Double.parseDouble(st.nextToken()); Double.parseDouble(st.nextToken()) Double.parseDouble Double st.nextToken() st.nextToken st public class Main {
  static InputReader in;
  static PrintWriter out;

  static class Solution {
    void solve() throws IOException {
      while (true) {
        String x = in.next();
        if (x.equals("0")) {
          break;
        }
        
        long sum = 0;
        
        for (int i = 0; i < x.length(); i++) {          
          sum += Integer.parseInt(x.substring(i, i+1));
        }
       
       out.println(sum);
      }
      
//      End solve()
    }
//    End Solution
}

  public static void main(String[] args) throws IOException {
    in = new InputReader(System.in);
    out = new PrintWriter(System.out);
    Solution solver = new Solution();
    solver.solve();
    out.close();
}

  static class InputReader {
    public BufferedReader br;
    public StringTokenizer st;

    public InputReader(InputStream stream) {
      br = new BufferedReader(new InputStreamReader(stream));
    }

    public int nextInt() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Integer.parseInt(st.nextToken());
    }

    public long nextLong() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Long.parseLong(st.nextToken());
    }

    public String next() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return st.nextToken();
    }

    public double nextDouble() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Double.parseDouble(st.nextToken());
    }


  }

} public class Main {
  static InputReader in;
  static PrintWriter out;

  static class Solution {
    void solve() throws IOException {
      while (true) {
        String x = in.next();
        if (x.equals("0")) {
          break;
        }
        
        long sum = 0;
        
        for (int i = 0; i < x.length(); i++) {          
          sum += Integer.parseInt(x.substring(i, i+1));
        }
       
       out.println(sum);
      }
      
//      End solve()
    }
//    End Solution
}

  public static void main(String[] args) throws IOException {
    in = new InputReader(System.in);
    out = new PrintWriter(System.out);
    Solution solver = new Solution();
    solver.solve();
    out.close();
}

  static class InputReader {
    public BufferedReader br;
    public StringTokenizer st;

    public InputReader(InputStream stream) {
      br = new BufferedReader(new InputStreamReader(stream));
    }

    public int nextInt() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Integer.parseInt(st.nextToken());
    }

    public long nextLong() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Long.parseLong(st.nextToken());
    }

    public String next() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return st.nextToken();
    }

    public double nextDouble() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Double.parseDouble(st.nextToken());
    }


  }

} Main
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.StringTokenizer;

public class Main {
  static InputReader in;
  static PrintWriter out;

  static class Solution {
    void solve() throws IOException {
      while (true) {
        String x = in.next();
        if (x.equals("0")) {
          break;
        }
        
        long sum = 0;
        
        for (int i = 0; i < x.length(); i++) {          
          sum += Integer.parseInt(x.substring(i, i+1));
        }
       
       out.println(sum);
      }
      
//      End solve()
    }
//    End Solution
}

  public static void main(String[] args) throws IOException {
    in = new InputReader(System.in);
    out = new PrintWriter(System.out);
    Solution solver = new Solution();
    solver.solve();
    out.close();
}

  static class InputReader {
    public BufferedReader br;
    public StringTokenizer st;

    public InputReader(InputStream stream) {
      br = new BufferedReader(new InputStreamReader(stream));
    }

    public int nextInt() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Integer.parseInt(st.nextToken());
    }

    public long nextLong() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Long.parseLong(st.nextToken());
    }

    public String next() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return st.nextToken();
    }

    public double nextDouble() throws IOException {
      while (st == null || !st.hasMoreTokens()) {
        st = new StringTokenizer(br.readLine());
      }
      return Double.parseDouble(st.nextToken());
    }


  }

}