You need to recall levels 49 and 50 to solve this one. Remember that in level 50, the block order was: 35/4/18/35, 5/7, 86, 71. You need to arrange the boxes in similar order in this level. So the boxes need to be placed in the following order:
4/18/35, 5
This will reveal a key which you can use to open the safe. Here you will find a matchbox. Use it to light 5 candles. This is because there were 3 lit candles in level 49 and 2 in level 50. So The sum of 3 and 2 is 5.
Now you can exit this level.
