This is an example puzzle. You can solve it the same way as you would solve competition puzzle, but result never stored. You can reveal an answer for the puzzle by clicking "Show answer" link.

Author: Andrey Bogdanov

Fill in some cell with digits from 1 to N. Each row and column should contain two empty cells and every digit exactly once. The numbers outside of the grid indicate the sum of the numbers between the two empty cells in that particular row or column.

**Grid control**:
Click at a cell reveals the value chooser. Click at the selected value changes the state of the cell.
More details about grid control are at the help page.