Chocolate bars

It is hard to overestimate the role of chocolate bars in traditional programming competitions. Firstly, the nutritional content of chocolate significantly increases the number of brilliant ideas among the participants of the Olympiad. Geometric shape of the tiles is usually a rectangle of size a \times b of square pieces 1 \times 1, which in turn recalls the model of many problems.

Given the size of one chocolate bar a \times b and the number of Olympiad participants $n$. The jury members want to determine the minimum number of chocolate bars, so that breaking the bars into single pieces, it will be possible to divide them equally among all $n$ participants. That is, each participant can receive equal number of square tiles 1 \times 1.