#include <bits/stdc++.h>   using namespace std;   int max(int &a, int &b) { return (a > b ? a : b); }   unsigned long long max(unsigned long long &a, unsigned long long &b) {     return (a > b ? a : b);   }   int min(int &a, int &b) { return (a < b ? a : b); }   long long int bits_needed(long long int val) {     long long int count = 0;     while (val) count++, val >>= 1;     return count;   }   int main() {     ios_base::sync_with_stdio(false);     cin.tie(NULL);     int t = 0, n = 0, i = 0;     long long int val = 0, prev = 0, ans = 0;     cin >> t;     while (t-- > 0) {       ans = 0;       cin >> n;       cin >> prev;       for (i = 1; i < n; i++) {         cin >> val;         if (val < prev) {           ans = max(ans, bits_needed(prev - val));         } else           prev = val;       }       cout << ans <<   n ;     }     return 0;   }   