#include <iostream>
using namespace std;
int main() {
int n, m , k=0;
cin>>n>>m;
int a[n*4+1]={0,};
for(int i=0; i<m; i++){
int x;
cin>>x;
a[x]=1;
}
for (int i = 1; i<=4*n; i+=2)
if(a[i]==0 and a[i+1]==0){
cout<<i<<" "<<i+1<<endl;
return 0;
}
for (int i=2 ; i<= 4*n; i+=4)
if(a[i]==0 and a[i+2]==0){
cout<<i<<" "<<i+2<<endl;
return 0;
}
for (int i=1 ; i<= 4*n; i+=4)
if(a[i]==0 and a[i+1]==0){
cout<<i<<" "<<i+1<<endl;
return 0;
}
for(int i=1; i<=4*n; i++){
if(a[i]==0){
cout<<i<<" ";
k++;
}
if(k==2) return 0;
}
}
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