package main
import (
    "fmt"
    "sort"
)
func main(){
    var n, g int
    fmt.Scan(&n)
    fmt.Scan(&g)
    t := make([]int, n)
    for i := 0; i < n; i++ {
        fmt.Scan(&t[i])
    }
    sort.Ints(t)
    var sp int
    sp = n / g
    var max, min, cnt, total, res float64
    for k, v := range t {
        total += float64(v)
        cnt += 1
        if cnt == float64(sp) || k + 1 == len(t) {
            res = total / cnt
            if max < res {
                if min == 0 {
                    min = max
                }
                max = res
            } else if min > res {
                min = res
            }
            total = 0
            cnt = 0
        }
    }
    fmt.Println(int(max - min))
}