local n = io.read("*n", "*l")
local str = io.read()
local a = {}
for v in str:gmatch("%d+") do
  table.insert(a, tonumber(v))
end
if #a == 3 then
  print('"assert"')
else
  a[2] = io.read("*n")
  a[3] = io.read("*n")
  table.sort(a)
  if a[1] == a[2] then print(a[1] + a[2]) else print(a[1] + a[3]) end
end