#include <stdio.h>
#include <algorithm>
using namespace std;

int n,v[810];

int caut_bin(int x)
{
	int i,step;
	for(step=1;step<n;step<<=1){
	for(i=1;step;step>>=1){
		if(v[i+step]<=x){
			i+=step;
			printf("%d ",i);
		}
	}
}
	return i;
}

int main()
{
	freopen("nrtri.in","r",stdin);
	freopen("nrtri.out","w",stdout);
	scanf("%d",&n);
	int j;
	for(j=1;j<=n;j++){
		scanf("%d",&v[j]);
	}
	sort(v+1,v+n+1);
	int m,a,s=0;;
	for(j=1;j<n;j++){
		for(m=j+1;m<=n;m++){
			a=caut_bin(v[j]+v[m])-m;
			printf("\n");
			s=s+a;
		}
	}
	printf("\n%d",s);
	return 0;
}