1 #include <vector> 2 #include <iostream> 3 #include <string> 4 #include <algorithm> 5 #include <limits> 6 #include <cstdio> 7  8 using namespace std; 9 10 int main(){11     int N;12     cin >> N;13     getchar();14 15     vector<string> lines;16     int shortest = 0x7fffffff;17     for (int i = 0; i < N; i++){18         string str;19         getline(cin, str);20 21         if (str.size() < shortest)22             shortest = str.size();23 24         lines.push_back(str);25     }26 27     int common_len = 0;28     for (int i = 0; i < shortest; i++){29         char ch = lines[0][lines[0].size() - i - 1];30 31         int cnt = 1;32         for (int j = 1; j < lines.size(); j++){33             string cur_str = lines[j];34             if (cur_str[cur_str.size() - i - 1] != ch)35                 break;36             cnt++;37         }38 39         if (cnt == lines.size())40             common_len++;41         else42             break;43     }44 45     if (common_len == 0)46         cout << "nai" << endl;47     else{48         string res = lines[0].substr(lines[0].size() - common_len, lines[0].size());49         cout << res << endl;50     }51 52     return 0;53 }