MARYBMW  BMW
Mary is very very happy. You would be happy too if your parents give you the latest model BMW for your birthday. She wants to try out her new car and that's why she is going to visit her grandma.
There is a graph with N vertices representing N cities and M edges representing bidirectional roads between some pairs of cities. We can assume that Mary lives in city 1 and her grandma lives in city N. Unfortunately, not everything is so good in life and examples are the speed limits. Mary decided to drive with permanent speed. Each of these M roads has a maximum permissible speed V that Mary can't exceed. Well, her whims don't end here. As a lover of the extreme experiences she wants to drive her expensive car as fast as possible.
You are to write a program to find the maximum speed that Mary can reach her grandma's city without having arguments with the policemen (for their own good).
Note: There may be more than one road between two cities.
Input
The first line of the input contains the number of tests – T (T <= 5). On the first line of each test case there are two integers – N (2 <= N <= 50000) and M (1 <= M <= 100000). On the next M lines there are three integers A, B, and V representing a bidirectional road between cities A and B with speed limit V where 1 <= V <= 10^18 (It's a BMW after all).
Output
On a single line print the maximum possible speed Mary can reach. If she can't reach her grandma's house, print 1.
Example
Input:1
4 5
1 2 80
3 1 20
2 3 60
4 3 300
2 4 90
Output:80
hide comments
auler_:
20200523 00:03:41
notice, n can be unreachable from 1. 

amansahu112:
20200416 14:50:42
100th AC .


cenation007:
20190820 14:20:30
fast input/output:)


shubham97361:
20190625 21:02:23
Just think little more about kruskal 

a_98:
20190523 15:54:02
My 100th AC :D :) 

ayushgupta1997:
20190224 08:45:03
use ios:: and "\n" to get AC if you are getting TLE! 

smso:
20190116 03:37:18
@febrin: thanks for the hint


febrin:
20190112 14:32:24
Time limit is fine and problem is interesting.


nadstratosfer:
20181103 05:33:10
Another genius setting time limit as if there was danger of brute force solutions sneaking in. Downvoting. 

ansh_gupta5076:
20180111 14:48:58
use fast I/0 to overcome TLE

Added by:  Extazy 
Date:  20151228 
Time limit:  0.5s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ASM64 GOSU JSMONKEY 