7560: [CSES Problem Set] Elevator Rides
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Description
There are $n$ people who want to get to the top of a building which has only one elevator. You know the weight of each person and the maximum allowed weight in the elevator. What is the minimum number of elevator rides?
Input
The first input line has two integers $n and $x$: the number of people and the maximum allowed weight in the elevator.
The second line has $n$ integers $w_1,w_2,\dots,w_n$: the weight of each person.
The second line has $n$ integers $w_1,w_2,\dots,w_n$: the weight of each person.
Output
Print one integer: the minimum number of rides.
Constraints
$1≤n≤20$
$1 \le x \le 10^9$
$1 \le w_i \le x$
$1 \le x \le 10^9$
$1 \le w_i \le x$
Sample 1 Input
4 10
4 8 6 1
Sample 1 Output
2