@Override
	public String toString() {
		StringBuilder sb = new StringBuilder();

		// Title row
		sb.append(String.format("%4s|", ""));
		for (int j = 0; j <= b.length; j++)
			sb.append(String.format("%4s|", (j > 0 ? b[j - 1] : "")));
		sb.append("\n");

		for (int i = 0; i <= a.length; i++) {
			sb.append(String.format("%4s|", (i > 0 ? a[i - 1] : ""))); // Column title
			for (int j = 0; j <= b.length; j++)
				sb.append(String.format("%4d|", score[i][j]));
			sb.append("\n");
		}
		return sb.toString();
	}