#D3387. Second Sum
Second Sum
Second Sum
Given is a permutation P of \{1, 2, \ldots, N\}.
For a pair (L, R) (1 \le L \lt R \le N), let X_{L, R} be the second largest value among P_L, P_{L+1}, \ldots, P_R.
Find \displaystyle \sum_{L=1}^{N-1} \sum_{R=L+1}^{N} X_{L,R}.
Constraints
- 2 \le N \le 10^5
- 1 \le P_i \le N
- P_i \neq P_j (i \neq j)
- All values in input are integers.
Input
Input is given from Standard Input in the following format:
N P_1 P_2 \ldots P_N
Output
Print \displaystyle \sum_{L=1}^{N-1} \sum_{R=L+1}^{N} X_{L,R}.
Examples
Input
3 2 3 1
Output
5
Input
5 1 2 3 4 5
Output
30
Input
8 8 2 7 3 4 5 6 1
Output
136
inputFormat
input are integers.
Input
Input is given from Standard Input in the following format:
N P_1 P_2 \ldots P_N
outputFormat
Output
Print \displaystyle \sum_{L=1}^{N-1} \sum_{R=L+1}^{N} X_{L,R}.
Examples
Input
3 2 3 1
Output
5
Input
5 1 2 3 4 5
Output
30
Input
8 8 2 7 3 4 5 6 1
Output
136
样例
5
1 2 3 4 5
30