import sys
input = sys.stdin.readline
N = int(input())
a = []
for _ in range(N):
  S = list(input())[: -1]
  if sorted(S) == S: a.append(S)

dp = [0] * 26
a.sort(key = lambda x: (max(x), min(x)))
for S in a:
  l = ord(min(S)) - ord("a")
  r = ord(max(S)) - ord("a")
  for i in range(l, -1, -1): dp[r] = max(dp[r], dp[i] + len(S))
print(max(dp))