It's Christmas time in the forest, and both the fox and the wolf
families are celebrating. The rather large fox family consists of two
parents as well as
little foxlings.
The parents have decided to give their children a special treat this
year – crackers! After all, it's a well-known fact that foxen love
crackers.
With such a big family, the parents can't afford that many crackers. As
such, they wish to minimize how many they give out, but still ensuring
that each foxling gets at least a bit. The parents can only give out
entire crackers, which can then be divided and passed around.
With this many children, not all of them know one another all that well.
The foxlings have names, of course, but their parents are computer
scientists, so they have also conveniently numbered them from
to
.
There are
unique two-way friendships among
the foxlings, where relationship
is described by the distinct
integers
and
, indicating
that foxling
is friends with foxling
, and vice versa.
When a foxling is given a cracker, he can use his tail to precisely
split it into as many pieces as he wants (the tails of foxen have many
fascinating uses). He can then pass these pieces around to his friends,
who can repeat this process themselves.
Input Specification
Line
: Two integers –
and
.
Next
lines: Two integers –
and
.
Output Specification
The minimum number of crackers that must be given out so that each fox
ends up with at least a bit of a cracker.
Sample Input
Copy
9 5
3 1
6 1
7 6
2 7
8 9
Sample Output
Copy
4
Explanation
The parents can give one cracker to foxling
, who will then split it
into three and give pieces to his friends (foxlings
and
). Foxling
can then give half of his piece to his other friend, foxling
.
They can give another cracker to foxling
, who will split it with
foxling
.
This leaves foxlings
and
, who have no friends (don't worry, foxen
have long since outgrown the need for friends), and who must be given
one cracker each. This brings the total up to
crackers.
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