Machine Input-Output — quick quiz

A word and number arrangement machine when given an input line of words and numbers rearranges them following a particular rule in each step. The following is an illustration of input and rearrangement: Input: 42 garden 18 flower 56 tree 29 plant 63 Step I: 18 42 garden flower 56 tree 29 plant 63 Step II: 18 garden 42 flower 56 tree 29 plant 63 Step III: 18 garden 29 42 flower 56 tree plant 63 Step IV: 18 garden 29 plant 42 flower 56 tree 63 Step V: 18 garden 29 plant 42 tree flower 56 63 Step VI: 18 garden 29 plant 42 tree 56 flower 63 Step VII: 18 garden 29 plant 42 tree 56 63 flower Step VII is the last step of the arrangement. As per the rules followed in the above steps, find the appropriate step for the given input: Input: 35 river 72 mountain 14 forest 48 valley 81 Which step number is the following output? 14 river 35 mountain 72 forest 48 valley 81