# 2751. Internet Service Providers

A group of N Internet Service Provider companies (ISPs) use a private communication channel that has a maximum capacity of C traffic units per second. Each company transfers T traffic units per second through the channel and gets a profit that is directly proportional to the factor T(C - T N). The problem is to compute T_optim, the smallest value of T that maximizes the total profit the N ISPs can get from using the channel. Notice that N, C, T, and T_optim are integer numbers.

### 输入格式

Write a program that reads sets of data from an input text file. Each data set corresponds to an instance of the problem above and contains two integral numbers – N and C – with values in the range from 0 to 109. The input data are separated by white spaces, are correct, and terminate with an end of file. For each data set the program computes the value of T_optim according to the problem instance that corresponds to the data set.

### 输出格式

The result is printed on the standard output from the beginning of a line. There must be no empty lines on the output. An example of input/output is shown below.

### 样例

Input
1 0
0 1
4 3
2 8
3 27
25 1000000000

Output
0
0
0
2
4
20000000


25 人解决，31 人已尝试。

28 份提交通过，共有 92 份提交。

4.5 EMB 奖励。