N, M, T = map(int, input().split())

links = [[] for _ in range(N)]
for _ in range(M):
    a, b = map(int, input().split())
    links[a].append(b)

s = {0}
for _ in range(T):
    t = set()
    for i in s:
        for j in links[i]:
            t.add(j)
    s = t
print(len(s))