n, edgeCount, timeLimit = map(int, input().split())
doubling = [[[False] * n for _ in range(n)] for _ in range(61)]

for _ in range(edgeCount):
    u, v = map(int, input().split())
    doubling[0][u][v] = True

for d in range(60):
    for u in range(n):
        for v in range(n):
            for w in range(n):
                doubling[d + 1][u][w] |= doubling[d][u][v] and doubling[d][v][w]

current = [False] * n
current[0] = True

for d in range(60):
    if ((timeLimit >> d) & 1) > 0:
        nxt = [False] * n
        for u in range(n):
            if current[u]:
                for v in range(n):
                    nxt[v] |= doubling[d][u][v]
        current = nxt

count = 0

for v in range(n):
    if current[v]:
        count += 1

print(count)