n = int(input())
L = [[] for i in range(26)]
for i in range(n):
    S = input()
    l = [-1]
    check = True
    for s in S:
        now = ord(s)-ord("a")
        if now < l[-1]:
            check = False
            break
        l.append(now)
    if check == False:
        continue
    L[l[1]].append([l[-1],len(l)-1])

dp = [0]*26

for i in range(26):
    dp[i] = max(dp[i],dp[i-1])
    if L[i] == []:
        continue
    L[i].sort()
    for r,le in L[i]:
        dp[r] = max(dp[r],dp[i]+le)
print(dp[-1])