from collections import deque
import sys
input = sys.stdin.readline

ans = []
T = int(input())

for _ in range(T) :
    N, K = map(int, input().split())
    
    build_info = [[] for _ in range(N+1)]
    dp = [-1]*(N+1)
    build_time = [0] + list(map(int, input().split()))
    indegree = [0]*(N+1)
    
    for _ in range(K) :
        u, v = map(int, input().split())
        build_info[u].append(v)
        indegree[v] += 1
    
    W = int(input())
    
    qu = deque()
    
    for i in range(1, N+1) :
        if indegree[i] == 0 :
            qu.append(i)
            dp[i] = build_time[i]
    
    while qu :
        now = qu.popleft()
        if now == W :
            break

        for next in build_info[now] :
            dp[next] = max(dp[next], dp[now] + build_time[next])
            
            indegree[next] -= 1
            if indegree[next] == 0 :
                qu.append(next)
    
    ans.append(str(dp[W]))

print('\n'.join(ans))