import java.io.*;

public class C_kosak
{
	public static void main(String pArgs[]) throws IOException
	{
		BufferedReader	in = new BufferedReader(new InputStreamReader(System.in));
		while (solve(in, System.out))
			;
		in.close();
	}
	
	private static boolean solve(BufferedReader pIn, PrintStream pOut) throws IOException
	{
		String		line;
		int			index, width, height;
		char[][]	matrix;
		
		//	行列のサイズを読む
		line = pIn.readLine();
		index = line.indexOf(' ');
		width = Integer.parseInt(line.substring(0, index));
		height = Integer.parseInt(line.substring(index + 1));
		if (width == 0 && height == 0)
			return false;
		matrix = new char[height][width];
		
		//	行列を読む
		for (int h = 0; h < height; h++) {
			line = pIn.readLine();
			for (int w = 0; w < width; w++)
				matrix[h][w] = line.charAt(w);
		}
		
		//	表を作成
		Cell[][]	table = new Cell[height + 1][width + 1];
		char		chr;
		String		longest, biggest;
		for (int h = height; h >= 0; h--)
			table[h][width] = new Cell("", "");
		for (int w = width; w >= 0; w--)
			table[height][w] = new Cell("", "");
		for (int h = height - 1; h >= 0; h--) {
			for (int w = width - 1; w >= 0; w--) {
				chr = matrix[h][w];
				if (chr == '0') {
					//	ゼロは長さには影響するが、数値の大きさには影響しない
					longest = "0" + Cell.max(table[h + 1][w].longest, table[h][w + 1].longest);
					biggest = Cell.max(table[h + 1][w].biggest, table[h][w + 1].biggest);
				} else if (chr >= '1' && chr <= '9') {
					//	先頭が非ゼロなので、最長文字列は最大文字列でもある
					longest = chr + Cell.max(table[h + 1][w].longest, table[h][w + 1].longest);
					biggest = longest;
				} else
					longest = biggest = "";
				table[h][w] = new Cell(longest, biggest);
			}
		}
		
		//	デバッグ用。表を出力する。
		/*
		for (int h = 0; h < height; h++) {
			for (int w = 0; w < width; w++) {
				System.out.print(table[h][w]);
				System.out.print(',');
			}
			System.out.println();
		}
		*/
		
		//	最大値を探して出力
		biggest = "";
		for (int h = 0; h < height; h++) {
			for (int w = 0; w < width; w++)
				biggest = Cell.max(table[h][w].biggest, biggest);
		}
		pOut.println(biggest == null ? "No secrets..." : biggest);
		
		return true;
	}	//	solve
	
	//	ある場所から始まる最長の数字列および（数値として）最大の数字列を保持する
	static class Cell {
		public String	longest, biggest;
		
		public Cell(String pLongest, String pBiggest)
		{
			longest = pLongest;
			biggest = pBiggest;
		}
		
		//	２つの数字列のうち、長い方（同じ長さなら、数値として大きい方）を返す
		public static String max(String pStr1, String pStr2)
		{
			if (pStr1.length() > pStr2.length())
				return pStr1;
			else if (pStr1.length() < pStr2.length())
				return pStr2;
			else if (pStr1.compareTo(pStr2) >= 0)
				return pStr1;
			else
				return pStr2;
		}
		
		public String toString()
		{
			return longest + "/" + biggest;
		}
	}	//	class Cell
}	//	class C_kosak