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There are many benefits to timing your practice, including:
To get from one point to another staying on shortest route you can only down or to the right.
Each shortest route can be described as a sequence:
(x0, x1, x2, x3) where xi >=0 - number of steps down on vertical i.
x0 + x1 + x2 + x3 = 2
Number of solutions to this equation is our answer.
2C4 + 1C4 = 10