import sys

data = sys.stdin.read().split()
if not data:
    exit()
n = int(data[0])
m = int(data[1])
k = int(data[2])
a = [0] * (n + 1)
max_val = 0
for i in range(1, n + 1):
    a[i] = int(data[2 + i])
    if a[i] > max_val:
        max_val = a[i]
adj = [[] for _ in range(n + 1)]
idx = 3 + n
for _ in range(m):
    u = int(data[idx])
    v = int(data[idx+1])
    adj[u].append(v)
    idx += 2
l = 1
r = max_val
ans = -1
while l <= r:
    mid = (l + r) // 2
    in_degree = [0] * (n + 1)
    valid_count = 0
    for u in range(1, n + 1):
        if a[u] <= mid:
            valid_count += 1
            for v in adj[u]:
                if a[v] <= mid:
                    in_degree[v] += 1
    q = []
    dp = [0] * (n + 1)
    possible = False
    for i in range(1, n + 1):
        if a[i] <= mid:
            dp[i] = 1
            if dp[i] >= k:
                possible = True
            if in_degree[i] == 0:
                q.append(i)
    head = 0
    visited_count = 0
    while head < len(q) and not possible:
        u = q[head]
        head += 1
        visited_count += 1
        for v in adj[u]:
            if a[v] <= mid:
                if dp[u] + 1 > dp[v]:
                    dp[v] = dp[u] + 1
                    if dp[v] >= k:
                        possible = True
                        break
                in_degree[v] -= 1
                if in_degree[v] == 0:
                    q.append(v)
    if visited_count < valid_count:
        possible = True
    if possible:
        ans = mid
        r = mid - 1
    else:
        l = mid + 1
print(ans)