#include <iostream>
#include <cstdio>
#include <cstdlib>
using namespace std;
 
int cmp(const void *a, const void *b) {
	return (*(int*)a-*(int*)b);
}
 
int main() {
	int n, l[2000], cnt, i, j, k;
	scanf("%d", &n);
	while(n) {
		cnt=0;
		for(i=0; i<n; i++) scanf("%d", &l[i]);
		qsort(l, n, sizeof(int), cmp);
		for(k=n-1; k>1; k--) {
			i=0; j=k-1;
			while(i<j) {
				if(l[k]>(l[i]+l[j])) { cnt+=j-i; i++; }
				else j--;
			}
		}
		printf("%d\n", cnt);
		scanf("%d", &n);
	}
	return 0;
}

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Mwo0IDIgMTAKMwoxIDIgMwo0CjUgMiA5IDYKMA==

3
4 2 10
3
1 2 3
4
5 2 9 6
0