There are $n$ slimes standing in a row, the $i^{th}$ one has size $A_i$. Merging two slimes of the same size $i$ will result in a slime of size $i + 1$.
Count the number of pairs $l \le r$ that merging all slimes $l,l+1,...,r$ results in one slime.
### Input
- The first line contains an integer $n$.
- The next line contains $n$ integers $A_i$.
### Output
- Print the number of pairs.
### Constraints
- $1 \le n \le 10^5$.
- $1 \le A_i \le 10^9$.
### Example
Input:
```
3
1 1 2
```
Output:
```
5
```