#include <bits/stdc++.h>   using namespace std;   int main() {     int t;     scanf( %d , &t);     while (t--) {       int n, ans = 0, num[101], temp, minn = 1e9 + 7, maxx = 0, ann;       for (int i = 1; i <= 100; i++) num[i] = 0;       scanf( %d , &n);       for (int i = 1; i <= n; i++) {         scanf( %d , &temp);         num[temp]++;         minn = min(minn, temp);         maxx = max(maxx, temp);       }       for (int i = 2; i <= maxx * 2; i++) {         int sum = 0;         for (int j = 1; j <= i / 2; j++)           if (j != i - j)             sum += min(num[j], num[i - j]);           else             sum += num[j] / 2;         if (sum > ans) {           ans = sum;         }       }       printf( %d n , ans);     }   }   