N = int(input())

def check(word):
    flg = True
    mi, mx = 'z', 'a'
    for s in word:
        if s < mx:
            flg = False
        mi = min(mi, s)
        mx = max(mx, s)
    return (flg, mi, mx, len(S))

lis = []

for i in range(N):
    S = input()
    ok, mi, mx, ln = check(S)
    if ok:
        lis.append([mi, mx, ln])

lis.sort(key=lambda x: (x[1], -x[2]))

ans = 0
last = 'a'
for mi, mx, leng in lis:
    if last > mi:
        continue
    ans += leng
    last = mx

print(ans)