第一次独立用map好开心
#include<iostream>
#include<map>
using namespace std;
int main (){
    
    
    int N,M;
    cin>>N>>M;
    
    while(N!=0&&M!=0){

    map<int,int> m;
    map<int,int>::iterator iter;

        for(int i=0;i<N*M;i++){
            int temp;
            cin>>temp;
            m[temp]++;
        }
        int max=0;
        int sec=0;
        int count=0;
        for(iter=m.begin();iter!=m.end();iter++){
            if(iter->second>max){
                max=iter->second;
            }
           
        }
        for(iter=m.begin();iter!=m.end();iter++){
            if(iter->second>sec&&iter->second!=max){
                sec=iter->second;
            }

        }
        for(iter=m.begin();iter!=m.end();iter++){
            if(iter->second==sec)cout<<iter->first<<" ";
        }
        cout<<endl;
        
        
        cin>>N>>M;
    }
    //system("pause");
    return 0;
}