Suppose the numbers 0, 1, 2,. . . , 9 were pushed onto a stack in that order but that pops to occur at random points between the various pushes. The following is a valid sequence in which the values in the stack could have been popped:

3, 2, 6, 5, 7, 4, 1, 0, 9, 8 Explain why it is not possible that 3, 2, 6, 4, 7, 5, 1, 0, 9, 8 is a valid sequence in which the values could have been popped off the stack.