The Bus With Eight Seats

One bus, cap seats, one long line — how many trips until everyone's at the museum? 🚌

You get the line of kids and the bus capacity cap. Print the number of trips needed (the last trip may run partly empty).

Example:

Input: line = ["a","b","c","d","e","f","g","h","i"], cap = 4 Output: 3

Trip 1 boards 4 kids, trip 2 boards 4 more, trip 3 boards the last 1 — 3 trips in total.