N = int(input())
A = input()
if " " in A:
  print("assert")
else:
  data = [0] * 3
  data[0] = int(A)
  for i in range(2):
    data[i + 1] = int(input())
  res = set()
  res.add(data[0] + data[1])
  res.add(data[1] + data[2])
  res.add(data[2] + data[0])
  print(sorted(list(res), reverse = True)[1])