n, m, k = read_line.split.map(&.to_i)
g = Array.new(n) { [] of {Int32, Int32} }
m.times do
  u, v, c = read_line.split.map(&.to_i.pred)
  g[u] << {v, c + 1}
  g[v] << {u, c + 1}
end
puts (0..2*10**5).bsearch { |x|
  que = Deque{0}
  dist = Array(Int32?).new(n, nil)
  dist[0] = 0
  while v = que.shift?
    d = dist[v].not_nil!
    g[v].each do |u, c|
      cost = c > x ? 1 : 0
      d2 = d + cost
      if (d3 = dist[u]).nil? || d2 < d3
        dist[u] = d2
        if cost == 0
          que.unshift u
        else
          que.push u
        end
      end
    end
  end
  dist.last.not_nil! < k
}