Pencils

Choose either set X or set Y, buy any number of copies of that one set, and pay the least to reach at least N pencils.

Easy2MathImplementationInterviewNo attempts yetTime limit2sMemory limit512 MB

Description

Examples2

Problem

JOI wants to buy $N$ pencils and goes to a nearby stationery shop.

The shop sells pencils only in fixed-size sets. Set $X$ holds $A$ pencils and costs $B$ yen. Set $Y$ holds $C$ pencils and costs $D$ yen.

JOI picks either set $X$ or set $Y$ and then buys as many copies of the chosen set as he likes. He cannot buy both kinds of set. Find the smallest amount of money needed to end up with at least $N$ pencils.

Input

The input is given from standard input in the following format.

N A B C D

Five integers are given on one line, separated by spaces.

Output

Print, on one line, the smallest amount of money JOI needs to get at least $N$ pencils.

Constraints

$1 \le N \le 1000$
$1 \le A \le 1000$
$1 \le B \le 1000$
$1 \le C \le 1000$
$1 \le D \le 1000$