#include <iostream>
#include <fstream>
#include <algorithm>
using namespace std;
ifstream f("nrtri.in");
ofstream g("nrtri.out");
int main()
{
    int v[808],n,s=0,hi,lo,mi,re=0;
    f>>n;
    for (int i=1;i<=n;i++)
        f>>v[i];
    sort (v+1,v+1+n);
    for (int i=2;i<=n-1;i++)
    {
        s=v[i]+v[i-1];
        lo=i;
        hi=n+1;
        while (hi-lo!=1)
        {
            mi=(hi+lo)/2;
            if (v[mi]<=s)
                lo=mi;
            else hi=mi;
        }
        cout<<i<<" "<<lo<<"\n";
        re=re+lo-i;
    }
    g<<re;
    return 0;
}