package main

import . "fmt"
import . "os"
import bf "bufio"

func main() {
	rd:=bf.NewReader(Stdin)
	var n,m int
	Fscan(rd,&n,&m)
	a := make([]int, n)
	for i := range a {
		Fscan(rd,&a[i])
	}
	lb, ub := 0, int(1e9)+1
	for lb+1 < ub {
		mid := (lb+ub)/2
		need, ca, ok := mid*m, 0, true
		for _, v := range a {
			if v+ca < need {
				ok=false
				break
			}
			ca = v+ca - need
		}
		if ok {
			lb = mid
		} else {
			ub = mid
		}
	}	
	Println(lb)
}