QOJ.ac

QOJ

Time Limit: 1 s Memory Limit: 512 MB Total points: 100 Difficulty: [show] Hackable ✓

#6493. Travel

Statistics

Travel

Little Y is an OIer who loves traveling. She plans to visit every city in country X.

Little Y has learned that there are $m$ bidirectional roads between the $n$ cities in country X. Each bidirectional road connects two cities. There are no two roads connecting the same pair of cities, and there are no roads connecting a city to itself. Furthermore, it is possible to reach any other city from any city by traveling along these roads. Little Y can only travel between cities using these roads.

Little Y's travel plan is as follows: she chooses an arbitrary city as the starting point, and then starts from the starting point. Each time, she can choose a road connected to the current city to move to a city she has not visited before, or backtrack to the previous city along the road she used to visit the current city for the first time. When Little Y returns to the starting point, she can choose to end the trip or continue traveling. It should be noted that Little Y requires that every city must be visited during the trip.

To make her trip more meaningful, Little Y decides to record the ID of each city as she arrives at it (including the starting point). She knows this will form a sequence of length $n$. She hopes that this sequence will be lexicographically as small as possible. Can you help her?

For two sequences $A$ and $B$ of length $n$, we say sequence $A$ is lexicographically smaller than $B$ if and only if there exists an integer $x$ such that the following conditions are met: For any $1 \le i < x$, the $i$-th element $A_i$ of sequence $A$ is equal to the $i$-th element $B_i$ of sequence $B$. The value of the $x$-th element of sequence $A$ is smaller than the value of the $x$-th element of sequence $B$.

Input

The input contains $m+1$ lines. The first line contains two integers $n, m$ ($m = n-1$ or $m = n$), separated by a space.

The next $m$ lines each contain two integers $u, v$ ($1 \le u, v \le n$), representing a road between city $u$ and city $v$, separated by a space.

Output

The output contains one line with $n$ integers, representing the lexicographically smallest sequence. Adjacent integers are separated by a space.

Examples

Input 1

6 5
1 3
2 3
2 5
3 4
4 6

Output 1

1 3 2 5 4 6

Input 2

6 6
1 3
2 3
2 5
3 4
4 5
4 6

Output 2

1 3 2 4 5 6

Input 3

(See travel/travel3.in and travel/travel3.ans in the provided directory)

Note: This example satisfies $m = n - 1$.

Input 4

(See travel/travel4.in and travel/travel4.ans in the provided directory)

Note: This example satisfies $m = n$.

Constraints

For 100% of the data and all examples, $1 \le n \le 5000$ and $m = n - 1$ or $m = n$.

The constraints for different test cases are as follows:

Test Case ID $n$ $m$ Special Property
1, 2, 3 10 None
4, 5 100 None
6, 7, 8 1000 At most two roads connected to each city
9, 10 1000 None
11, 12, 13 5000 At most three roads connected to each city
14, 15 5000 None
16, 17 10 None
18, 19 100 None
20, 21, 22 1000 At most two roads connected to each city
23, 24, 25 5000 None

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