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

goto = [[set() for j in range(N)] for i in range(60)]
for i in range(N):
    goto[0][i].add(i)
for i in range(M):
    a, b = map(int, input().split())
    goto[1][a].add(b)
for i in range(2, 60):
    for j in range(N):
        goto[i][j] = set()
        for g in goto[i - 1][j]:
            goto[i][j] |= goto[i - 1][g]
ans = set([0])
for i in range(60):
    if T >> i & 1:
        nex = set()
        for g in ans:
            nex |= goto[i + 1][g]
        ans = nex
print(len(ans))