#include<iostream>
#include<cstdio>
#include<cmath>
using namespace std;
int xl[190000]={0};
inline int mn(){
	freopen("ppairing.in","r",stdin);
	freopen("ppairing.out","w",stdout);
	register int n,c;
	register int cl;
	register int f=0;
	scanf("%d%d",&n,&c);
	for(register int i=1;i<=c;++i){
		scanf("%d",&cl);
		for(int j=f+1;j<=f+cl;++j){
			xl[j]=i;
		}
		f+=cl;
	}
	for(register int i=1;i<=n/2;++i){
		printf("%d ",xl[i]);
		printf("%d\n",xl[i+n/2]);
	}
	return 0;
}
int ll=mn();
int main(){;}