public int[][] readMatrix() {
Scanner sc = new Scanner(System.in);
String input = sc.nextLine();
String[] parts = input.split(":");
if (parts.length == 3) {
int m = Integer.parseInt(parts[0]);
int n = Integer.parseInt(parts[1]);
String[] entries = parts[3].split(",");
if (entries.length == m*n) {
int[][] matrix = new int[m][n];
for (int i = 0; i < entries.length; i++) {
matrix[i / n][i % m] = Integer.parseInt(entries[i]);
}
return matrix;
}
}
return null;
}