import numpy as np
n, m, t = map(int, input().split())
p = np.zeros((n, n), dtype = np.bool)
for _ in range(m):
  a, b = map(int, input().split())
  p[a][b] = 1
res = np.zeros((n, 1), dtype = np.bool)
res[0][0] = 1
while t > 0:
  if t & 1:
    res = p @ res
  t >>= 1
  p = p @ p
print(sum(i[0] for i in res))