There are 10 red marbles, 20 blue marbles, and 30 green marbles. 10 people, in turn, choose one marble. Each person can choose a total of 1 red, 2 blue, 3 green. Each chosen marble is placed in a continous row to create a row of all 60 marbles. How many different rows can be created? Can you write a program that would print out each different row? For example:

rrrrrrrrrrbbbbbbbbbbbbbbbbbbbbgggggggggggggggggggggggggggggg
rrrrrrrrrrbbbbbbbbbbbbbbbbbbbgbggggggggggggggggggggggggggggg
rrrrrrrrrrbbbbbbbbbbbbbbbbbbbggbgggggggggggggggggggggggggggg