Given a list lst and a number N, create a new list that contains each number of lst at most N times without reordering. For example if N = 2, and the input is [1,2,3,1,2,1,2,3], you take [1,2,3,1,2], drop the next [1,2] since this would lead to 1 and 2 being in the result 3 times, and then take 3, which leads to [1,2,3,1,2,3].
deleteNth([1, 1, 1, 1], 2) // return [1,1]
deleteNth([20, 37, 20, 21], 1) // return [20,37,21]