local n = io.read("*n") local parent = {} for i = 1, n do parent[i] = i end local function uf_findroot(idx) local idx_update = idx while parent[idx] ~= idx do idx = parent[idx] end while parent[idx_update] ~= idx do parent[idx_update], idx_update = idx, parent[idx_update] end return idx end local as, bs = {}, {} for i = 1, n do local a, b = io.read("*n", "*n") as[i], bs[i] = a, b local ra, rb = uf_findroot(a), uf_findroot(b) parent[b], parent[rb] = ra, ra end local group = {} local g_e = {} local edge = {} local edgecnt = {} for i = 1, n do group[i] = {} g_e[i] = {} edge[i] = {} edgecnt[i] = 0 end for i = 1, n do local r = uf_findroot(i) table.insert(group[r], i) end for i = 1, n do local a, b = as[i], bs[i] local r = uf_findroot(a) table.insert(g_e[r], i) edge[a][i], edge[b][i] = true, true edgecnt[a] = edgecnt[a] + 1 edgecnt[b] = edgecnt[b] + 1 end for i = 1, n do if #group[i] ~= #g_e[i] then print("No") os.exit() end end print("Yes") local ans = {} for i = 1, n do ans[i] = 0 end local function solve(gi) local tasks = {} local done = 0 for i = 1, #group[gi] do local src = group[gi][i] if edgecnt[src] == 1 then table.insert(tasks, src) end end while done < #tasks do done = done + 1 local src = tasks[done] local ei = next(edge[src]) ans[ei] = src local dst = as[ei] == src and bs[ei] or as[ei] edge[dst][ei] = nil edgecnt[dst] = edgecnt[dst] - 1 if edgecnt[dst] == 1 then table.insert(tasks, dst) end end if done == #group[gi] then return end local ring_spos = false for i = 1, #group[gi] do local src = group[gi][i] if edgecnt[src] == 2 then ring_spos = src table.insert(tasks, src) break end end while done < #tasks do done = done + 1 local src = tasks[done] local ei = next(edge[src]) ans[ei] = src local dst = as[ei] == src and bs[ei] or as[ei] edge[dst][ei] = nil edgecnt[dst] = edgecnt[dst] - 1 if edgecnt[dst] == 1 then table.insert(tasks, dst) end end end for i = 1, n do solve(i) end print(table.concat(ans, "\n"))