# Practice on Toph

Participate in exhilarating programming contests, solve unique algorithm and data structure challenges and be a part of an awesome community.

# Boltu vs Balti

Boltu and Balti are two friends. Boltu is a great programmer whereas Balti is a newbie programmer. But Balti thinks that he is also a great programmer, but Boltu can’t accept Balti as a great programmer. Now Boltu challenges Balti to solve a task to prove himself as a great programmer. Balti accepts that challenge.

The task is Boltu will give him any 2 numbers N and M , he (Balti) has to find the sum of all numbers in the range N and M (inclusive).
Balti knows that the equation of finding sum from 1 to n is `$ n(n+1)/2 $`

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Balti is getting stuck to find it from N to M. Now he wants your help. Help him to win this challenge by solving this problem.

## Input

Each line of input contains two integers **N** and **M** (0 ≤ N,M ≤ 10^{9}). The numbers are separated by exactly one space. The end of file will indicate the end of input.

## Output

You have to find the sum of numbers between N and M and print it as follows:

```
Sum of X to Y is: Z;
```

Here X is the smaller number, Y is the larger number and Z is the sum of all numbers between N and M (inclusive).

## Samples

Input | Output |
---|---|

2 6 3 7 | Sum of 2 to 6 is -> 20; Sum of 3 to 7 is -> 25; |

In the first sample test case the sum of numbers from 2 to 6 is `$ 2+3+4+5+6 = 20 $`

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In the second sample test case the sum of numbers from 3 to 7 is `$ 3+4+5+6+7 = 25 $`

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