n,m,t = map(int,input().split())
db = [[set() for j in range(59)] for i in range(n)]

for i in range(m):
    a,b = map(int,input().split())
    db[a][0].add(b)
for i in range(1,59):
    for j in range(n):
        for k in db[j][i-1]:
            db[j][i] |= db[k][i-1]
ans = set([0])
for i in range(59):
    if t >> i & 1:
        nex = set()
        for j in ans:
            nex |= db[j][i]
        ans = nex
print(len(ans))