In the two positions, the common face is 3. From the first die, 1 and 4 are adjacent to 3. From the second, 6 and 2 are adjacent to 3. So, 1, 4, 6, and 2 are all adjacent to 3. The only remaining number is 5, which must be opposite to 3. If 5 is on top, 3 will be at the bottom.