1 #include <stdio.h>
 2 #include <cstring>
 3 #include <algorithm>
 4 using namespace std;
 5 #define clr(x) memset(x, 0, sizeof(x))
 6 #define max(a, b) (a)>(b)?(a):(b)
 7 const int INF = 0x1f1f1f1f;
 8
 9 int dp[1<<15][15], f[15][15];
10 char arr[15][15];
11
12 int lenn(char *a, char *b)
13 {
14     int lena = strlen(a), lenb = strlen(b);
15     int max = 0;
16     int sum;
17     for(int i = 0; i < lena; ++i){
18         sum = 0;
19         for(int j = 0; j < lenb && i+j < lena; ++j){
20             if(a[i+j] == b[j]) sum++;
21         }
22         if(sum > max) max = sum;
23     }
24
25     for(int i = 0; i < lenb; ++i){
26         sum = 0;
27         for(int j = 0; j < lena && i+j < lenb; ++j)
28             if(b[i+j] == a[j]) sum++;
29         if(sum > max) max = sum;
30     }
31     return max;
32 }
33
34 int main()
35 {
36     int i, j, k;
37     int n, st, sta;
38     while(scanf("%d", &n) != EOF)
39     {
40         if(n == 0) break;
41         clr(f), clr(dp);
42         st = (1<<n) - 1;
43
44         for(i = 0; i < n; ++i)
45             scanf("%s", arr[i]);
46
47         for(i = 0; i < n; ++i)
48         for(j = 0; j < n; ++j)
49         if(i != j){
50             f[i][j] = f[j][i] = lenn(arr[i], arr[j]);
51         }
52
53         memset(dp, -1, sizeof(dp));
54         for(i = 0; i < n; ++i)
55             dp[1<<i][i] = 0;
56
57         for(i = 1; i < st; ++i)
58         for(j = 0; j < n; ++j)
59         if(dp[i][j] != -1)
60             for(k = 0; k < n; ++k)
61             if(!(i&(1<<k))){
62                 sta = i+(1<<k);
63                 dp[sta][k] = max(dp[sta][k], dp[i][j]+f[j][k]);
64             }
65
66         int ans = 0;
67         for(i = 0; i < n; ++i)
68         if(dp[st][i] > ans) ans = dp[st][i];
69
70         printf("%d\n", ans);
71
72
73     }
74     return 0;
75 }