def mmult(A, B):
    n, m, l = len(A), len(B), len(B[0])
    ret = [[0]*l for _ in range(n)]
    for i in range(n):
        for j in range(m):
            for k in range(l):
                if A[i][j] and B[j][k]:
                    ret[i][k] = 1
    return ret
def mpow(A, n):
    if n == 0: return [[1 if i == j else 0 for j in range(len(A))] for i in range(len(A))]
    if n % 2: return mmult(mpow(A, n-1), A)
    return mpow(mmult(A, A), n//2)

N,M,T = map(int,input().split())
A = [[0 for j in range(N)] for i in range(N)]
for i in range(M):
    a,b = map(int,input().split())
    if not A[b][a]:
        A[b][a] = 1

A = mpow(A,T)
B = [[1]] + [[0]] * (N-1)
A = mmult(A,B)

res = 0
for i in range(N):
    if A[i][0]:
        res += 1

print(res)