## Filling Jars

Animesh has empty candy jars, numbered from to , with infinite capacity. He performs operations. Each operation is described by integers, , , and . Here, and are indices of the jars, and is the number of candies to be added inside each jar whose index lies between and (both inclusive). Can you tell the average number of candies after operations?

**Input Format**

The first line contains two integers, and , separated by a single space.

lines follow; each of them contains three integers, , , and , separated by spaces.

**Constraints**

**Output Format**

A single line containing the average number of candies across jars, *rounded down* to the nearest integer.

**Note**: *Rounded down* means finding the greatest integer which is less than or equal to the given number. E.g. *13.65* and *13.23* are rounded down to *13*, while *12.98* is rounded down to *12*.

**Sample Input**

```
5 3
1 2 100
2 5 100
3 4 100
```

**Sample Output**

```
160
```

**Explanation**

Initially each of the jars contains *0* candies

```
0 0 0 0 0
```

First operation:

```
100 100 0 0 0
```

Second operation:

```
100 200 100 100 100
```

Third operation:

```
100 200 200 200 100
```

Total = *800*, Average = *800/5* = *160*