100 atcoder#ABC212E. [ABC212E] Safety Journey

[ABC212E] Safety Journey

Score : 500500 points

Problem Statement

The Republic of AtCoder has NN cities, called City 11, City 22, \ldots, City NN. Initially, there was a bidirectional road between every pair of different cities, but MM of these roads have become unusable due to deterioration over time. More specifically, for each 1iM1\leq i \leq M, the road connecting City UiU_i and City ViV_i has become unusable.

Takahashi will go for a KK-day trip that starts and ends in City 11. Formally speaking, a KK-day trip that starts and ends in City 11 is a sequence of K+1K+1 cities (A0,A1,,AK)(A_0, A_1, \ldots, A_K) such that A0=AK=1A_0=A_K=1 holds and for each 0iK10\leq i\leq K-1, AiA_i and Ai+1A_{i+1} are different and there is still a usable road connecting City AiA_i and City Ai+1A_{i+1}.

Print the number of different KK-day trips that start and end in City 11, modulo 998244353998244353. Here, two KK-day trips (A0,A1,,AK)(A_0, A_1, \ldots, A_K) and (B0,B1,,BK)(B_0, B_1, \ldots, B_K) are said to be different when there exists an ii such that AiBiA_i\neq B_i.

Constraints

  • 2N50002 \leq N \leq 5000
  • $0 \leq M \leq \min\left( \frac{N(N-1)}{2},5000 \right)$
  • 2K50002 \leq K \leq 5000
  • $1 \leq U_i
  • All pairs (Ui,Vi)(U_i, V_i) are pairwise distinct.
  • All values in input are integers.

Input

Input is given from Standard Input in the following format:

NN MM KK

U1U_1 V1V_1

::

UMU_M VMV_M

Output

Print the answer.

3 1 4
2 3
4

There are four different trips as follows.

  • (1,2,1,2,11,2,1,2,1)
  • (1,2,1,3,11,2,1,3,1)
  • (1,3,1,2,11,3,1,2,1)
  • (1,3,1,3,11,3,1,3,1)

No other trip is valid, so we should print 44.

3 3 3
1 2
1 3
2 3
0

No road remains usable, so there is no valid trip.

5 3 100
1 2
4 5
2 3
428417047