#include <cstdio>
#include <vector>
#include <unordered_set>
#include <algorithm>
using namespace std;
string getLCS(string str1, string str2) {
vector<vector<int> > record(str1.length(), vector<int>(str2.length()));
int maxLen = 0, maxEnd = 0;
for(int i=0; i<static_cast<int>(str1.length()); ++i)
for (int j = 0; j < static_cast<int>(str2.length()); ++j) {
if (str1[i] == str2[j]) {
if (i == 0 || j == 0) {
record[i][j] = 1;
}
else {
record[i][j] = record[i - 1][j - 1] + 1;
}
}
else {
record[i][j] = 0;
}
if (record[i][j] > maxLen) {
maxLen = record[i][j];
maxEnd = i;
}
}
return str1.substr(maxEnd - maxLen + 1, maxLen);
}
int main(void) {
printf("%d\n", ret);
return 0;
}