It should not be too much of a problem if you make sure to keep the like pairs on the same axle, that is both on the front matching and both on the back matching. You also want to keep the best tyres on the back.
If you were to mix them so both of one size were on the left and a different size on the right then in an emergency stop you would not stop straight. The reason to keep the best tyres on the back is likewise safety in an emergency because if your back tyres are not as good or better than the front, you may end up looking where you have been and not where you are going.