#include <sstream>
#include <iostream>
#include <vector>
using namespace std;
vector<int> temp;
int main()
{
string line;
getline(cin, line);
istringstream f(line);
string s;
while (getline(f, s, ' ')) {
temp.push_back(stoi(s));
}
vector<int> piramida[temp[0]];
for(int i=0; i<temp[0]; i++){
getline(cin, line);
istringstream ff(line);
while (getline(ff, s, ' ')) {
piramida[i].push_back(stoi(s));
}
}
bool finish = false;
int suma = 0;
int i=0;
int rocznik =piramida[0][0];
while(suma<temp[1]){
suma += piramida[i].size();
for(int k=0;k<piramida[i].size();k++){
if(piramida[i][k] < rocznik){
rocznik = piramida[i][k];
}
}
i++;
}
cout << rocznik << "\n";
return 0;
}