Floor Number

题意翻译

- 除第一层有 $1,2$ 两个房间外，其余层皆有 $x$ 个房间。这些房间的门牌号从第一层起逐层递增。 - 给出 $n$ 和 $x$，求出门牌号为 $n$ 的房间在第几层。 - 数据组数 $t\le1000$，$1\le n,x\le1000$。

题目描述

Vasya goes to visit his classmate Petya. Vasya knows that Petya's apartment number is $ n $ . There is only one entrance in Petya's house and the distribution of apartments is the following: the first floor contains $ 2 $ apartments, every other floor contains $ x $ apartments each. Apartments are numbered starting from one, from the first floor. I.e. apartments on the first floor have numbers $ 1 $ and $ 2 $ , apartments on the second floor have numbers from $ 3 $ to $ (x + 2) $ , apartments on the third floor have numbers from $ (x + 3) $ to $ (2 \cdot x + 2) $ , and so on. Your task is to find the number of floor on which Petya lives. Assume that the house is always high enough to fit at least $ n $ apartments. You have to answer $ t $ independent test cases.

输入输出格式

输入格式

The first line of the input contains one integer $ t $ ( $ 1 \le t \le 1000 $ ) — the number of test cases. Then $ t $ test cases follow. The only line of the test case contains two integers $ n $ and $ x $ ( $ 1 \le n, x \le 1000 $ ) — the number of Petya's apartment and the number of apartments on each floor of the house except the first one (there are two apartments on the first floor).

输出格式

For each test case, print the answer: the number of floor on which Petya lives.

输入输出样例

输入样例 #1

4
7 3
1 5
22 5
987 13

输出样例 #1

3
1
5
77

说明

Consider the first test case of the example: the first floor contains apartments with numbers $ 1 $ and $ 2 $ , the second one contains apartments with numbers $ 3 $ , $ 4 $ and $ 5 $ , the third one contains apartments with numbers $ 6 $ , $ 7 $ and $ 8 $ . Therefore, Petya lives on the third floor. In the second test case of the example, Petya lives in the apartment $ 1 $ which is on the first floor.