def main0(n,m,t,ab):
  # 愚直。ダブリング。O(n^2)
  g=[set() for _ in range(n)]
  for a,b in ab:
    a,b=a-1,b-1
    g[a].add(b)
  ary=[[set()]*60 for _ in range(n)]
  # ary[v][k]:頂点vの2^k秒後にいる可能性のある頂点の集合
  for v in range(n):ary[v][0]=g[v]
  for k in range(1,60):
    for v in range(n):
      tmp=set()
      for u in ary[v][k-1]:
        tmp|=ary[u][k-1]
      ary[v][k]=tmp
  now={0}
  for i in range(60):
    if t&(1<<i):
      nxt=set()
      for v in now:
        nxt|=ary[v][i]
      now=nxt
  return len(now)

if __name__=='__main__':
  n,m,t=map(int,input().split())
  ab=[list(map(int,input().split())) for _ in range(m)]
  ret0=main0(n,m,t,ab)
  print(ret0)