This is true. I was inferring that the only colours available were those mentioned in the OP.But there could be other colors. For example
Red = 1
Green = 1
Black = 1
Pink = 2
This would leave 5.
If there is at least one other color and we agree that all three of the mentioned colors each have at least one, then there must be one of each of those colors, and a total of two of the other color or colors.