Problem: After waking up at hh:mm, Andrew realised that he had forgotten to feed his only cat for yet another time (guess why there's only one cat). The cat's current hunger level is H points, moreover each minute without food increases his hunger by D points.

At any time Andrew can visit the store where tasty buns are sold (you can assume that is doesn't take time to get to the store and back). One such bun costs C roubles and decreases hunger by N points. Since the demand for bakery drops heavily in the evening, there is a special 20% discount for buns starting from 20:00 (note that the cost might become rational). Of course, buns cannot be sold by parts.

Determine the minimum amount of money Andrew has to spend in order to feed his cat. The cat is considered fed if its hunger level is less than or equal to zero.

Input

The first line contains two integers hh and mm (00 ≤ hh ≤ 23, 00 ≤ mm ≤ 59) — the time of Andrew's awakening.

The second line contains four integers H, D, C and N (1 ≤ H ≤ 105, 1 ≤ D, C, N ≤ 102).

Output

Output the minimum amount of money to within three decimal digits. You answer is considered correct, if its absolute or relative error does not exceed 10 - 4.

Formally, let your answer be a, and the jury's answer be b. Your answer is considered correct if <image>.

Examples

Input

19 00
255 1 100 1


Output

25200.0000


Input

17 41
1000 6 15 11


Output

1365.0000

Note

In the first sample Andrew can visit the store at exactly 20:00. The cat's hunger will be equal to 315, hence it will be necessary to purchase 315 buns. The discount makes the final answer 25200 roubles.

In the second sample it's optimal to visit the store right after he wakes up. Then he'll have to buy 91 bins per 15 roubles each and spend a total of 1365 roubles.

Solution (in JAVA):

Solution:
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Comparator;
import java.util.HashMap;
import java.util.HashSet;
import java.util.InputMismatchException;
import java.util.StringTokenizer;
/*
 * 
 * daiict
 *
 * 
 * 
 */

public class pprac
{
	FastScanner in;
	PrintWriter out;

	static int countc = 0;
	static int minm = countc;

	static ArrayList[] adj;
	static ArrayList[] aadj;
	static int last;
	static int n;
	static int m;

	static int[] dp1;
	static int[] dp2;
	static int color[];
	static int visited[];
	static int[] arr;
	static long[] brr;
	static double ans;
	static int array[];
	static int start[];
	static int finish[];
	static int pref[];
	static int tree[];
	static int maxval = 32;

	static int ttt[];
	static int sum = 0;
	static String s;

	static int cc = 0;
	static long min = Long.MAX_VALUE;

	static ArrayList<Integer> segt[];

	// for dfs do not delete
	static int dir[][] =
	{
			{ 1, 0 },
			{ 0, 1 },
			{ 0, -1 },
			{ -1, 0 } };

	static int[] seg;
	static long count = 1;
	static long mod = (long) 1e9 + 7;

	static int parent[];
	static int size[];

	static int[] l;
	static int[] r;
	static int[] next;
	static int[] cnt;
	static int[] block;

	static int bblock = 1001;

	static HashSet<String> set;
	static HashSet<String> set2;

	static int low[];
	static int disc[];
	static int time;
	static int acn[];

	static HashMap<Long, Integer> map;

	static class Pair implements Comparable<Pair>
	{
		int x;
		int y;
		int i;

		Pair(int l, int m, int i)
		{

			this.x = l;
			this.y = m;
			this.i = i;

		}

		public int compareTo(Pair p)
		{

			if (this.x / bblock == p.x / bblock)
			{
				return (int) (this.y - p.y);
			}
			return (int) (this.x / bblock - p.x / bblock);
		}

		public String toString()
		{
			return x + " " + y;
		}

		public boolean equals(Object o)
		{
			if (o instanceof Pair)
			{
				Pair a = (Pair) o;

				return this.x == a.x;
			}

			return false;
		}

		public int hashCode()
		{
			return new Long(x).hashCode() * 31 + new Long(y).hashCode();
		}

	}

	public static int gcd(int a, int b)
	{
		if (b == 0)
			return a;
		return gcd(b, a % b);
	}

	void build(int n)
	{ // build the tree
		for (int i = n - 1; i > 0; --i)
			seg[i] = Math.min(seg[i << 1], seg[i << 1 | 1]);
	}

	public static void modify(int p, int val, int n)
	{ // set value at position
		// p
		for (seg[p += n] = val; p > 1; p >>= 1)
			seg[p >> 1] = Math.min(seg[p], seg[p ^ 1]);
	}

	int query(int l, int r, int n)
	{ // sum on interval [l, r)
		int res = Integer.MAX_VALUE;

		if (l > r)
		{
			return res;
		}

		for (l += n, r += n; l < r; l >>= 1, r >>= 1)
		{
			if ((l & 1) == 1)
				res = Math.min(res, seg[l++]);
			if ((r & 1) == 1)
				res = Math.min(res, seg[--r]);
		}
		return res;
	}

	// public static void update(int x,int val){
	// while(x<=maxval){
	// tree[x] += val;
	// x = (x&-x);
	// }
	// }

	public static int read(int idx)
	{
		int sum = 0;

		while (idx >= 0)
		{
			sum += tree[idx];
			idx -= (idx & (-idx));
		}

		return sum;
	}

	public static int find(int i)
	{
		if (parent[i] != i)
		{
			return find(parent[i]);
		}

		return i;
	}

	public static void union(int a, int b)
	{
		int x = find(a);
		int y = find(b);

		if (x != y)
		{
			if (size[x] > size[y])
			{
				size[x] += size[y];
				parent[y] = x;
			} else
			{
				size[y] += size[x];
				parent[x] = y;
			}
		}
	}

			/* static */ void solve() throws NumberFormatException, InputMismatchException, IOException
	{

		// Scanner in = new Scanner(System.in);

		int n = in.nextInt();
		int m = in.nextInt();

		double a = in.nextDouble();
		double b = in.nextDouble();
		double c = in.nextDouble();
		double d = in.nextDouble();

		double min = 0;

		if (n >= 20)
		{
			double cc = Math.ceil(a / d) * c;
			cc = cc * 0.8;
			out.println(cc);
		} else
		{
			min = (20 - n - 1) * 60 + (60 - m);
			double dd = a;
			a = min * b + a;

			double cc = Math.ceil(a / d) * c;
			cc = cc * 0.8;

			cc = Math.min(cc, Math.ceil(dd / d) * c);
			out.println(cc);
		}

	}

	public static void dfs(int i, int l)
	{
		if (visited[i] == 1)
		{
			return;
		}

		visited[i] = 1;

		if (adj[i].size() > l)
		{
			countc++;
		}

		for (int j = 0; j < adj[i].size(); j++)
		{
			dfs((int) adj[i].get(j), adj[i].size());
		}

	}

	public static void add(int i)
	{
		low[disc[i]]++;
		disc[i]++;
	}

	public static void uu(int arr[], int i, int f)
	{
		if (i == 1)
		{
			return;
		}
		int next = i / 2;
		int x = 0;
		if (i % 2 == 0)
		{
			x = i + 1;
		} else
		{
			x = i - 1;
		}

		if (f == 1)
		{
			arr[next] = arr[i] ^ arr[x];
		} else
		{
			arr[next] = arr[i] | arr[x];
		}

		uu(arr, next, 1 - f);
	}

	public static String reverse(String s)
	{

		String ans = "";

		for (int i = s.length() - 1; i >= 0; i--)
		{
			ans += s.charAt(i);
		}

		return ans;

	}

	public static long sum(long x)
	{
		return x < 10 ? x : x % 10 + sum(x / 10);
	}

	public static long gcd(long x, long y)
	{
		if (x == 0)
			return y;
		else
			return gcd(y % x, x);
	}

	static long inv(long x, long mod)
	{
		long r, y;
		for (r = 1, y = mod - 2; y != 0; x = x * x % mod, y >>= 1)
		{
			if ((y & 1) == 1)
				r = r * x % mod;

		}
		return r;
	}

	public static long pow(long x, long y, long n)
	{
		if (y == 0)
			return 1 % n;
		if (y % 2 == 0)
		{
			long z = pow(x, y / 2, n);
			return (z * z) % n;
		}
		return ((x % n) * pow(x, y - 1, n)) % n;
	}

	public static boolean isPrime(long a)
	{
		// Corner cases
		if (a <= 1)
			return false;
		if (a <= 3)
			return true;

		// This is checked so that we can skip
		// middle five numbers in below loop
		if (a % 2 == 0 || a % 3 == 0)
			return false;

		for (long i = 5; i * i <= a; i = i + 6)
			if (a % i == 0 || a % (i + 2) == 0)
				return false;

		return true;
	}

	void run() throws NumberFormatException, InputMismatchException, IOException
	{
		in = new FastScanner();
		out = new PrintWriter(System.out);

		solve();

		out.close();
	}

	class FastScanner
	{
		BufferedReader br;
		StringTokenizer st;

		public FastScanner()
		{
			br = new BufferedReader(new InputStreamReader(System.in));
		}

		String next()
		{
			while (st == null || !st.hasMoreTokens())
			{
				try
				{
					st = new StringTokenizer(in.br.readLine());
				} catch (IOException e)
				{
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			}
			return st.nextToken();
		}

		int nextInt()
		{
			return Integer.parseInt(next());
		}

		long nextLong()
		{
			return Long.parseLong(next());
		}

		double nextDouble()
		{
			return Double.parseDouble(next());
		}
	}

	public static void main(String[] args) throws NumberFormatException, InputMismatchException, IOException
	{
		// new Thread(null ,new Runnable(){
		// public void run(){
		// try{
		//
		// test();
		//
		// } catch(Exception e){
		// e.printStackTrace();
		// }
		// }
		// },"1",1<<26).start();
		// }
		// static StringBuilder sb;
		// public static void test() throws IOException{
		// sb=new StringBuilder();
		// int t=1;
		// while(t-->0){
		//
		// solve();
		//
		// }
		//

		new pprac().run();
	}

}

class Node
{
	int a;
	int b;

	public Node(int i, int j)
	{
		this.a = i;
		this.b = j;

	}

}

class MyComp implements Comparator<String>
{

	int c = 0;

	MyComp(int d)
	{
		c = d;
	}

	@Override
	public int compare(String a, String b)
	{

		// < == -1

		String arr[] = a.split(" ");
		String brr[] = b.split(" ");

		return arr[c].compareTo(brr[c]);

	}

}

class MyComp2 implements Comparator<Node>
{

	@Override
	public int compare(Node a, Node b)
	{

		// < == -1

		if (a.b > b.b)
		{
			return -1;
		} else
		{
			return 1;
		}

	}

}