package main

import (
	"fmt"
)

func main() {
	var n int
	if _, err := fmt.Scan(&n); err != nil {
		return
	}
	p := make([]float64, n)
	q := make([]float64, n)
	qc := make([]float64, n)
	P := 1.0

	for i := 0; i < n; i++ {
		fmt.Scan(&p[i])
		p[i] /= 100.0
		q[i] = 1.0 - p[i]
		qc[i] = q[i]
		P *= p[i]
	}

	ans := float64(n)
	for iter := 0; iter < 1000000; iter++ {
		if 1.0-P < 1e-12 {
			break
		}
		ans += 1.0 - P
		bestJ := -1
		bestVal := -1.0
		for j := 0; j < n; j++ {
			if qc[j] == 0 || qc[j] == 1.0 {
				continue
			}
			val := qc[j] * p[j] / (1.0 - qc[j])
			if val > bestVal {
				bestVal = val
				bestJ = j
			}
		}
		if bestJ == -1 {
			break
		}
		P *= (1.0 - qc[bestJ]*q[bestJ]) / (1.0 - qc[bestJ])
		qc[bestJ] *= q[bestJ]
	}

	fmt.Printf("%.9f\n", ans)
}