The aim of the puzzle is to mark all blocks as.

Right beside each row and under each column are one or more numbers. Each numerical value corresponds exactly to the length of a block of boxes to be marked. The numbers in a row always have to be marked as blocks in the grid from left to right and from top to bottom in the corresponding order. 

There must be at least one empty box between two blocks. The position of a block as well as the distance to the next block is logically compelling due to the combination of all numbers. You have up to five times the opportunity to mark a wrong box. This will be highlighted in red.

Good luck!