import java.io.*;
import java.util.*;


public class Main_yukicoder553 {

	private static Scanner sc;
	private static Printer pr;

	private static void solve() {
		int n = sc.nextInt();

		int[] r = new int[n];
		for (int i = 0; i < n; i++) {
			r[i] = sc.nextInt();
		}

		double gsum = 0;
		for (int i = 1; i <= n; i++) {
			gsum += g(r[i - 1]) * Math.pow(0.9, i);
		}
		gsum /= 9.0 * (1 - Math.pow(0.9, n));

//		pr.println(gsum);
//		pr.println((double)1 / g(gsum));
//		pr.println(f(n));

//		pr.println((double)1 / g(gsum) - f(n));
		pr.println((int)(Math.log(gsum) / Math.log(2) * 800 - f(n)));
	}

	private static double f(int x) {
		double ret = 0.1 * Math.sqrt(1 - Math.pow(0.81, x)) / (1 - Math.pow(0.9, x));
		ret -= 0.1;
		ret /= 0.1 * Math.sqrt(1 - 0.81) / (1 - 0.9) - 0.1;
		ret *= 1200;

		return ret;
	}

	private static double g(double x) {
		return Math.pow(2, x / 800);
	}

	// ---------------------------------------------------
	public static void main(String[] args) {
		sc = new Scanner(System.in);
		pr = new Printer(System.out);

		solve();

		pr.close();
		sc.close();
	}

	private static class Printer extends PrintWriter {
		Printer(PrintStream out) {
			super(out);
		}
	}
}