In a dark closet there are boots lying in disarray: 10 pairs of black and 10 pai

In a dark closet there are boots lying in disarray: 10 pairs of black and 10 pairs of brown. How many shoes must be taken so that among them there is at least one pair (left and right shoe) of the same color? (In the dark, it is impossible to distinguish not only the color of the shoe, but also the left from the right.)