N = int(input())

S = []
for _ in range(N):
    s = input()
    l = list(s)
    if l == sorted(l):
        S.append(s)
        
S.sort(key=lambda x: x[-1])

ans = 0
t = 'a'
for s in S:
    if t <= s[0]:
        ans += len(s)
        t = s[-1]
print(ans)