def aa(mat,t):
    global n
    res=[[0]*n for i in range(n)];res[0][0]=1
    while t:
        if t&1:
            res=bb(res,mat)
        t>>=1;mat=bb(mat,mat)
    return res

def bb(q,w):
    global n
    res=[[0]*n for i in range(n)]
    for i in range(n):
        for j in range(n):
            for l in range(n):
                res[j][l]|=q[j][i]&w[i][l]
    return res

n,m,t=map(int,input().split())
mat=[[0]*n for i in range(n)]
for i in range(m):
    a,b=map(int,input().split());mat[a][b]=1
ans=aa(mat,t)
c=0
for i in range(n):
    c+=ans[0][i]
print(c)