local n, m, p = io.read("*n", "*n", "*n")
local s, g = io.read("*n", "*n")
local edge = {}
for i = 1, n do
  edge[i] = {}
end
for i = 1, m do
  local a, b = io.read("*n", "*n")
  table.insert(edge[a], b)
  table.insert(edge[b], a)
end
local inf = 1000000007

local function solve(spos)
  local len = {}
  for i = 1, 2 * n do
    len[i] = inf
  end
  len[spos] = 0
  local tasks = {spos}
  local done = 0
  while done < #tasks do
    done = done + 1
    local src = tasks[done]
    if src <= n then
      for j = 1, #edge[src] do
        local dst = edge[src][j] + n
        if len[dst] == inf then
          len[dst] = len[src] + 1
          table.insert(tasks, dst)
        end
      end
    else
      for j = 1, #edge[src - n] do
        local dst = edge[src - n][j]
        if len[dst] == inf then
          len[dst] = len[src] + 1
          table.insert(tasks, dst)
        end
      end
    end
  end
  return len
end
local slen = solve(s)
local glen = solve(g)
if p % 2 == 0 then
  local ret = {}
  for i = 1, n do
    if slen[i] + glen[i] <= p or slen[i + n] + glen[i + n] <= p then
      table.insert(ret, i)
    end
  end
  if #ret == 0 then print(-1)
  else
    print(#ret)
    print(table.concat(ret, "\n"))
  end
else
  local ret = {}
  for i = 1, n do
    if slen[i] + glen[i + n] <= p or slen[i + n] + glen[i] <= p then
      table.insert(ret, i)
    end
  end
  if #ret == 0 then print(-1)
  else
    print(#ret)
    print(table.concat(ret, "\n"))
  end
end