Everyone knows the rules of sudoku, and we present to you not such an untwisted, but no less interesting puzzle CalcuDoku. It is based on sudoku, but with additions that complicate the task a bit. According to the rules, you must fill the cells with numbers that should not be repeated vertically or horizontally. But at the same time, you need to consider the numbers that are located in the upper left corners of the cells, which are surrounded by a bold line. There are mathematical signs next to them, which means that the number you place in the cell will be different.