The Byteburg's street network consists of intersections linked by
two-way street segments. Recently, the Byteburg was chosen to host the upcoming duathlon championship. This competition consists of two legs: a running leg, followed by a cycling leg.
The route for the competition should be constructed in the following way. First, three distinct intersections ,
, and
should be chosen for start, change, and finish stations. Then the route for the competition should be built. The route should start in
, go through
and end in
. For safety reasons, the route should visit each intersection at most once.
Before planning the route, the mayor wants to calculate the number of ways to choose intersections ,
, and
in such a way that it is possible to build the route for them. Help him to calculate this number.
Input
The first line contains integers and
: number of intersections, and number of roads. Next
lines contain descriptions of roads
. Each road is described with pair of integers
,
, the indices of intersections connected by the road
. For each pair of intersections, there is at most one road connecting them.
Output
Output the number of ways to choose intersections ,
, and
for start, change, and finish stations, in such a way that it is possible to build the route for competition.
Scoring
Subtask 1 (points: 5)
,
Subtask 2 (points: 11)
,
Subtask 3 (points: 8)
, there are at most two roads that end in each intersection.
Subtask 4 (points: 10)
, there are no cycles in the street network. The cycle is the sequence of
distinct intersections
, such that there is a road connecting
with
for all
from
to
, and there is a road connecting
and
.
Subtask 5 (points: 13)
, there are no cycles in the street network.
Subtask 6 (points: 15)
, for each intersection there is at most one cycle that contains it.
Subtask 7 (points: 20)
, for each intersection there is at most one cycle that contains it.
Subtask 8 (points: 8)
,
Subtask 9 (points: 10)
,
Sample Input 1
4 3
1 2
2 3
3 4
Sample Output 1
8
Sample Input 2
4 4
1 2
2 3
3 4
4 2
Sample Output 2
14
Explanation
In the first example there are 8 ways to choose the triple :
,
,
,
,
,
,
,
.
In the second example there are 14 ways to choose the triple :
,
,
,
,
,
,
,
,
,
,
,
,
,
.
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