package main import ( "bufio" "fmt" "os" "sort" "strconv" ) func out(x ...interface{}) { fmt.Println(x...) } var sc = bufio.NewScanner(os.Stdin) func getInt() int { sc.Scan() i, e := strconv.Atoi(sc.Text()) if e != nil { panic(e) } return i } func getInts(N int) []int { ret := make([]int, N) for i := 0; i < N; i++ { ret[i] = getInt() } return ret } func getString() string { sc.Scan() return sc.Text() } // min, max, asub, absなど基本関数 func max(a, b int) int { if a > b { return a } return b } func min(a, b int) int { if a < b { return a } return b } func asub(a, b int) int { if a > b { return a - b } return b - a } func abs(a int) int { if a >= 0 { return a } return -a } func lowerBound(a []int, x int) int { idx := sort.Search(len(a), func(i int) bool { return a[i] >= x }) return idx } func upperBound(a []int, x int) int { idx := sort.Search(len(a), func(i int) bool { return a[i] > x }) return idx } const inf = int(1e18) var B, N int var c []int var ans int func calc(p int) int { b := B cnt := 0 for i := 0; i < N; i++ { cnt += abs(p - c[i]) b += c[i] - p } if b < 0 { return inf } ans = min(ans, cnt) return cnt } func main() { sc.Split(bufio.ScanWords) B, N = getInt(), getInt() c = getInts(N) ans = inf l := 0 r := B for _, e := range c { r += e } r /= N for r-l > 10 { m0 := (l + l + r) / 3 m1 := (l + r + r) / 3 if calc(m0) <= calc(m1) { r = m1 } else { l = m0 } } for i := max(0, l-100); i < l+100; i++ { calc(i) } out(ans) }