The first line contains the number of cities n. 1≤n≤1000
The second line contains the number of buses m. 1≤m≤100000
Each of the next m lines describes one bus with the number of its start city, the number of its destination city, and its fare, in that order. A fare is an integer that is at least 0 and less than 100000. No bus starts and ends at the same city, and several buses may run the same route.
The last line contains the start city A and the destination city B of the trip you must plan. A and B are different.