#define HAVE_STRUCT_TIMESPEC

 #include<bits/stdc++.h>

 using namespace std;

 pair<int,string>pr[];

 bool cmp(pair<int,string>a,pair<int,string>b){

     if(a.first!=b.first)

         return a.first<b.first;

     return a.second>b.second;

 }

 string ans[];

 int main(){

     ios::sync_with_stdio(false);

     cin.tie(NULL);

     cout.tie(NULL);

     int n,k;

     cin>>n>>k;

     for(int i=;i<=n;++i)

         cin>>pr[i].second>>pr[i].first;

     sort(pr+,pr++n,cmp);

     int m=n;

     int x=n-n/k*k+n/k;

     int cnt=x;

     int temp=;

     int t=;

     int flag=-;

     while(cnt--){

         ans[x/++temp]=pr[m--].second;

         if(flag<)

             ++t;

         temp=t*flag;

         flag=-flag;

     }

     int num=x;

     for(int i=;i<k;++i){

         int cnt=n/k;

         int temp=;

         int t=;

         int flag=-;

         while(cnt--){

             ans[num+n/k/++temp]=pr[m--].second;

             if(flag<)

                 ++t;

             temp=t*flag;

             flag=-flag;

         }

         num+=n/k;

     }

     for(int i=;i<=x;++i){

         cout<<ans[i];

         if(i<x)

             cout<<" ";

         else

             cout<<"\n";

     }

     for(int i=x+;i<=n;++i){

         cout<<ans[i];

         if((i-x)%(n/k))

             cout<<" ";

         else if(i<n)

             cout<<"\n";

     }

     return ;

 }