#include <bits/stdc++.h>   using namespace std;   char s[20005];   struct SuffixArray {     int wa[20005], wb[20005], cnt[20005], wv[20005];     int rk[20005], height[20005];     int sa[20005];     bool cmp(int r[], int a, int b, int l) {       return r[a] == r[b] && r[a + l] == r[b + l];     }     void calcSA(char r[], int n, int m) {       int i, j, p, *x = wa, *y = wb;       for (i = 0; i < m; ++i) cnt[i] = 0;       for (i = 0; i < n; ++i) cnt[x[i] = r[i]]++;       for (i = 1; i < m; ++i) cnt[i] += cnt[i - 1];       for (i = n - 1; i >= 0; --i) sa[--cnt[x[i]]] = i;       for (j = 1, p = 1; p < n; j *= 2, m = p) {         for (p = 0, i = n - j; i < n; ++i) y[p++] = i;         for (i = 0; i < n; ++i)           if (sa[i] >= j) y[p++] = sa[i] - j;         for (i = 0; i < n; ++i) wv[i] = x[y[i]];         for (i = 0; i < m; ++i) cnt[i] = 0;         for (i = 0; i < n; ++i) cnt[wv[i]]++;         for (i = 1; i < m; ++i) cnt[i] += cnt[i - 1];         for (i = n - 1; i >= 0; --i) sa[--cnt[wv[i]]] = y[i];         for (swap(x, y), p = 1, x[sa[0]] = 0, i = 1; i < n; ++i)           x[sa[i]] = cmp(y, sa[i - 1], sa[i], j) ? p - 1 : p++;       }     }     void calcHeight(char r[], int n) {       int i, j, k = 0;       for (i = 0; i <= n; ++i) rk[sa[i]] = i;       for (i = 0; i < n; height[rk[i++]] = k)         for (k ? k-- : 0, j = sa[rk[i] - 1]; r[i + k] == r[j + k]; k++)           ;     }     bool solve(int k, int n, int div) {       int ca = 0, cb = 0;       for (int i = 1; i <= n; i++) {         if (height[i] < k) {           if (ca == 1 && cb == 1) return true;           ca = 0;           cb = 0;           if (sa[i] < div)             ca++;           else if (sa[i] > div)             cb++;           continue;         }         if (sa[i] < div)           ca++;         else if (sa[i] > div)           cb++;       }       return ca == 1 && cb == 1;     }   } suf;   char a[20005], b[20005];   int main() {     scanf( %s %s , a, b);     int n = strlen(a), m = strlen(b);     strcpy(s, a);     s[n] =  # ;     strcpy(s + n + 1, b);     int tot = n + m + 1;     suf.calcSA(s, tot + 1, 128);     suf.calcHeight(s, tot);     int ret = -1;     for (int i = 1; i <= n; i++) {       if (suf.solve(i, tot, n)) {         ret = i;         break;       }     }     printf( %d n , ret);     return 0;   }   