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 } func getf() float64 { sc.Scan() f, _ := strconv.ParseFloat(sc.Text(), 64) return f } func prime(N int, p float64) int { a := make([]float64, N+1) for i := 2; i <= N; i++ { a[i] = 1.0 } for i := 2; i <= N; i++ { for j := i * 2; j <= N; j += i { a[j] *= (1 - p) } } sum := 0.0 for i := 2; i <= N; i++ { sum += a[i] } out(sum) return 0 } func main() { sc.Split(bufio.ScanWords) N, p := getInt(), getf() prime(N, p) }