There are n stations and m directed roads between them.
One day, Chiaki is going from the s-th station to the t-th station, then back to the s-th station. Doing so, he needs to buy tickets for stations he passes. The price the tickets for the i-th station is p_i. If Chiaki buys a ticket for the i-th station, he can passes the station as many times as he wants. Find the minimum price of tickets to buy.
There are multiple test cases. The first line of the input contains an integer T (1≤T≤200) indicating the number of test cases. For each test case:
The first line of each test case contains four integers n, m, s and t (1≤n≤200, 0≤m≤n×(n−1), 1≤s,t≤n). The second line contains n integers p_1,p_2,…,p_n (1≤p_i≤100). The i-th of the following m lines contains two integers a_i and b_i, which denote a road from the a_i station to the b_i-th station (1≤a_i,b_i≤n).
The sum of all n does not exceed 200.
For each test case, output an integer denoting the answer. Print −1 for no solution.