#include <cstdio>
#include <iostream>
#include <math.h>
#include <string>
#include <sstream>
#include <iomanip>
#include <stdio.h>
#include <stdlib.h>
#include <ctime>
#include <string.h>
#include <algorithm>
#include <queue>
#include <stack>
#include <vector>
#include <map>
#include <set>

using namespace std;

struct compare {
    bool operator() (const string& lhs, const string& rhs) const{
        int s,s1,s2,p1=0,p2=0;
        while(lhs[p1]=='0')p1++;
        while(rhs[p2]=='0')p2++;
        s1=lhs.size(),s2=rhs.size();
        s=min(s1-p1,s2-p2);
        if(s1-p1==s2-p2)
            for(int x=0;x<s;x++)
                if(lhs[p1+x]!=rhs[p2+x])
                    return lhs[p1+x]<rhs[p2+x];
        return s1-p1<s2-p2;
    }
};
map<string,int,compare>p;
int main(){
    char c[1500];
    int n,k,pp=0;
    scanf("%d %d",&n,&k);
    for(int x=0;x<n;x++){
        scanf("%s",c);
        p[c]++;
    }
    int a;
    map<string,int,compare>::iterator xx=p.begin();
    while(xx->second>1)
        xx++;
    for(int y=1;y<k;y++){
        while(xx->second>1)xx++;
        xx++;
    }
    printf("%s\n",xx->first.c_str());
}