JOI '17 Final P4 - Commuter Pass
View as PDFJOI-kun is living in a city with  stations. The stations are numbered from 
 to 
. There are 
 railways numbered from 
 to 
. The railway 
 (
) connects the station 
 and the station 
 in both directions, and the fare is 
 yen.
JOI-kun is living near the station , and goes to the IOI high school near the station 
. He is planning to buy a commuter pass connecting these two stations. When he buys a commuter pass, he needs to choose a route between the station 
 and the station 
 with minimum cost. Using this commuter pass, he can take any railway contained in a chosen route in any direction without additional costs.
JOI-kun often goes to bookstores near the station  and the station 
. Therefore, he wants to buy a commuter pass so that the cost from the station 
 to the station 
 is minimized. When he moves from the station 
 to the station 
, he first chooses a route from the station 
 to the station 
. Then the fare he has to pay is
yen if the railway
is contained in a route chosen when he buys a commuter pass, or
yen if the railway
is not contained in a route chosen when he buys a commuter pass.
The sum of the above fare is the cost from the station  to the station 
. He wants to know the minimum cost from the station 
 to the station 
 if he chooses a route appropriately when he buys a commuter pass.
Input Specification
The first line of input contains two space separated integers , 
. This means the city JOI-kun lives in has 
 stations and 
 railways.
The second line contains two space separated integers , 
 (
). This means JOI-kun is planning to buy a commuter pass from the station 
 to the station 
.
The third line contains two space separated integers , 
 (
). This means JOI-kun wants to minimize the cost from the station 
 to the station 
.
Each of the following  lines contains three space separated integers 
, 
, 
 (
, 
). The railway 
 connects the station 
 and the station 
 in both directions, and the fare is 
 yen.
Output Specification
Write one line to the standard output. The output should contain the minimum cost from the station  to the station 
 if he chooses a route appropriately when he buys a commuter pass.
Constraints
In all test cases, , 
, 
 or 
.
In  test cases, 
.
In another  test cases, there is a unique route with minimum cost from the station 
 to the station 
.
In another  test cases, 
.
Sample Input 1
6 6
1 6
1 4
1 2 1
2 3 1
3 5 1
2 4 3
4 5 2
5 6 1
Sample Output 1
2
Sample Input 2
8 8
5 7
6 8
1 2 2
2 3 3
3 4 4
1 4 1
1 5 5
2 6 6
3 7 7
4 8 8
Sample Output 2
15
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