n = io.read("*n")
a = {}
for i = 1, n do
  a[i] = io.read("*n")
end

l = {true}
t = {}
t[a[1]] = true
for i = 2, n do
  ai = a[i]
  if t[ai] then
    for j = i, n do
      l[j] = false
    end
    break
  else
    l[i] = true
    t[ai] = true
  end
end
r = {}
for i = 1, n do r[i] = false end
r[n] = true
t = {}
t[a[n]] = true
for i = n - 1, 1, -1 do
  ai = a[i]
  if t[ai] then
    for j = i, 1, -1 do
      r[j] = false
    end
    break
  else
    r[i] = true
    t[ai] = true
  end
end
ans = {}
for i = 1, n - 1 do
  if l[i] and r[i + 1] then
    table.insert(ans, i)
  end
end
print(#ans)
print(table.concat(ans, " "))