# 1160. Date with MM

Tomorrow I will have a date with a MM but unfortunatelly I forgot the specific time.

It seems to be between M o’clock & N o’clock.So I choose sometime between the span to

be there and wait for her(the waiting hours should be within t hours).

So what’s the probability can I meet her(assuming that she will never wait for me)

### 输入格式

3 real numbers M,N,T

### 输出格式

The probability should be remain 3 digits of fraction

### 样例

Input
8.00 9.00 0.5
hint:0.5表示半个小时,8.5表示8点半

Output
0.375


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5.7 EMB 奖励。