local n = io.read("*n") local edge = {} local edgecnt = {} local l_to_r = {} for i = 1, n do edge[i] = {} edgecnt[i] = 0 l_to_r[i] = true end local ea, eb = {}, {} for i = 1, n do local a, b = io.read("*n", "*n") ea[i], eb[i] = a, b edge[a][i] = true edge[b][i] = true edgecnt[a] = edgecnt[a] + 1 edgecnt[b] = edgecnt[b] + 1 end local tasks = {} for i = 1, n do if edgecnt[i] == 1 then table.insert(tasks, i) end end local done = 0 while done < #tasks do done = done + 1 local src = tasks[done] local ei = next(edge[src]) local dst = ea[ei] + eb[ei] - src if eb[ei] == src then l_to_r[ei] = false end edge[src][ei] = nil edge[dst][ei] = nil edgecnt[src] = 0 edgecnt[dst] = edgecnt[dst] - 1 if edgecnt[dst] == 1 then table.insert(tasks, dst) end end local spos = 0 for i = 1, n do if edgecnt[i] == 2 then spos = i break end end tasks = {} do local ei = next(edge[spos]) local dst = ea[ei] + eb[ei] - spos edge[spos][ei] = nil if ea[ei] == spos then l_to_r[ei] = false end table.insert(tasks, spos) end done = 0 while done < #tasks do done = done + 1 local src = tasks[done] local ei = next(edge[src]) if not ei then break end local dst = ea[ei] + eb[ei] - src if eb[ei] == src then l_to_r[ei] = false end edge[src][ei] = nil edge[dst][ei] = nil table.insert(tasks, dst) end for i = 1, n do print(l_to_r[i] and "->" or "<-") end