for _ in range(int(input())):
n, k = map(int, input().split())
print(k*(n//k) + (k//2 if n%k >= k//2 else n%k))#include<bits/stdc++.h>
using namespace std;
int main()
{
int t;
cin>>t;
while(t--)
{
long long n,m;
cin>>n>>m;
cout<<((n/m)*m)+min(n%m,m/2)<<endl;
}
}
1669E - 2-Letter Strings | 483A - Counterexample |
3C - Tic-tac-toe | 1669F - Eating Candies |
1323B - Count Subrectangles | 991C - Candies |
1463A - Dungeon | 1671D - Insert a Progression |
1671A - String Building | 1671B - Consecutive Points Segment |
1671C - Dolce Vita | 1669G - Fall Down |
4D - Mysterious Present | 1316B - String Modification |
1204A - BowWow and the Timetable | 508B - Anton and currency you all know |
1672A - Log Chopping | 300A - Array |
48D - Permutations | 677C - Vanya and Label |
1583B - Omkar and Heavenly Tree | 1703C - Cypher |
1511C - Yet Another Card Deck | 1698A - XOR Mixup |
1702E - Split Into Two Sets | 1703B - ICPC Balloons |
1702F - Equate Multisets | 1700A - Optimal Path |
665C - Simple Strings | 1708A - Difference Operations |