class MatrixMul {
    public static void main(String[] args) {
        int[][] a = {{1,2},{3,4}};
        int[][] b = {{2,0},{1,2}};
        int[][] c = new int[2][2];
        for (int i=0;i<2;i++)
            for (int j=0;j<2;j++)
                for (int k=0;k<2;k++)
                    c[i][j]+=a[i][k]*b[k][j];
        for (int[] row:c) {
            for (int val:row) 
                System.out.print(val+" ");
            System.out.println();
        }
    }
}