### PROBLEM LINK:

**Author:** Vasia Antoniuk

**Tester:** Mahbubul Hasan and Sunny Aggarwal

**Editorialist:** Balajiganapathi Senthilnathan

**Russian Translator:** Sergey Kulik

**Mandarian Translator:** Minako Kojima

### DIFFICULTY:

Easy

### PREREQUISITES:

None

### PROBLEM:

What is the probability that two persons meet if one of them comes at any time from 0 to T_1, uniformly at random, and waits for t_1 units of time while the other person comes at any time from 0 to T_2 and waits for t_2 units of time.

### SHORT EXPLANATION

Suppose x_1 is the time at which the first person arrives and x_2 for second person. Then note that the following inequalities must hold for them to meet:

x_1 \le x_2 + t_2 and x_2 \le x_1 + t_1

See the figure for an example. Now we just have to find the area of the shaded region. That divided by the whole area (T_1 * T_2) gives the answer.

### EXPLANATION:

Coming soon

#### Time Complexity:

O(1)