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

n, m, k = map(int, readline().split())
petals = [int(readline()) for _ in range(n)]
for i in range(n):
    petals[i] -= 1
adj = [[] for _ in range(n)]
for _ in range(m):
    a, b = map(int, readline().split())
    adj[a-1].append(b-1)

ans = 0;
for i in range(n):
    diff = k-1 - petals[i]
    ans += diff
    for j in adj[i]:
        petals[j] = (petals[j] + diff) % k
print(ans)