#abc260f. [abc260_f]Find 4-cycle

[abc260_f]Find 4-cycle

Problem Statement

We have a simple undirected graph GG with (S+T)(S+T) vertices and MM edges. The vertices are numbered 11 through (S+T)(S+T), and the edges are numbered 11 through MM. Edge ii connects Vertices uiu_i and viv_i.
Here, vertex sets V1=lbrace1,2,dots,SrbraceV_1 = \\lbrace 1, 2,\\dots, S\\rbrace and V2=lbraceS+1,S+2,dots,S+TrbraceV_2 = \\lbrace S+1, S+2, \\dots, S+T \\rbrace are both independent sets.

A cycle of length 44 is called a 4-cycle.
If GG contains a 4-cycle, choose any of them and print the vertices in the cycle. You may print the vertices in any order.
If GG does not contain a 4-cycle, print -1.

What is an independent set? An independent set of a graph GG is a set VV' of some of the vertices in GG such that no two vertices of VV' have an edge between them.

Constraints

  • 2leqSleq3times1052 \\leq S \\leq 3 \\times 10^5
  • 2leqTleq30002 \\leq T \\leq 3000
  • 4leqMleqmin(StimesT,3times105)4 \\leq M \\leq \\min(S \\times T,3 \\times 10^5)
  • 1lequileqS1 \\leq u_i \\leq S
  • S+1leqvileqS+TS + 1 \\leq v_i \\leq S + T
  • If ineqji \\neq j, then (ui,vi)neq(uj,vj)(u_i, v_i) \\neq (u_j, v_j).
  • All values in input are integers.

Input

Input is given from Standard Input in the following format:

SS TT MM u1u_1 v1v_1 u2u_2 v2v_2 vdots\\vdots uMu_M vMv_M

Output

If GG contains a 4-cycle, choose any of them, and print the indices of the four distinct vertices in the cycle. (The order of the vertices does not matter.)
If GG does not contain a 4-cycle, print -1.


Sample Input 1

2 3 5
1 3
1 4
1 5
2 4
2 5

Sample Output 1

1 2 4 5

There are edges between Vertices 11 and 44, 44 and 22, 22 and 55, and 55 and 11, so Vertices 11, 22, 44, and 55 form a 4-cycle. Thus, 11, 22, 44, and 55 should be printed.
The vertices may be printed in any order. Besides the Sample Output, 2 5 1 4 is also considered correct, for example.


Sample Input 2

3 2 4
1 4
1 5
2 5
3 5

Sample Output 2

-1

Some inputs may give GG without a 4-cycle.


Sample Input 3

4 5 9
3 5
1 8
3 7
1 9
4 6
2 7
4 8
1 7
2 9

Sample Output 3

1 7 2 9