def dot(mtr0,mtr1):
  a,b=len(mtr0),len(mtr1[0])
  t=len(mtr0[0])
  if t!=len(mtr1):return None
  ret=[[0]*b for _ in range(a)]
  for i in range(a):
    for j in range(b):
      tmp=0
      for k in range(t):
        tmp+=mtr0[i][k]*mtr1[k][j]
      if tmp>0:tmp=1
      ret[i][j]=tmp
  return ret

def main0(n,m,t,ab):
  # ダブリング。O(n^2)
  g=[[0]*n for _ in range(n)]
  for a,b in ab:
    g[b][a]=1
  vc=[[0] for _ in range(n)]
  vc[0][0]=1
  while t:
    if t%2==1:vc=dot(g,vc)
    g=dot(g,g)
    t>>=1
  ans=0
  for i in range(n):
    if vc[i][0]==1:
      ans+=1
  return ans
  
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)