def main():
    n, m, k = map(int, input().split())
    p = [int(input()) - 1 for _ in range(n)]
    dag = [[] for _ in range(n)]
    for _ in range(m):
        u, v = map(int, input().split())
        dag[u - 1].append(v - 1)

    ans = 0
    for u in range(n):
        hits = k - 1 - p[u]
        ans += hits
        p[u] += hits
        for v in dag[u]:
            p[v] = (p[v] + hits) % k

    assert all(x == k - 1 for x in p)
    print(ans)

if __name__ == "__main__":
    main()