Score : 1200 points
In Takahashi's mind, there is always an integer sequence of length 2 \times 10^9 + 1: A = (A_{-10^9}, A_{-10^9 + 1}, ..., A_{10^9 - 1}, A_{10^9}) and an integer P.
Initially, all the elements in the sequence A in Takahashi's mind are 0, and the value of the integer P is 0.
When Takahashi eats symbols +
, -
, >
and <
, the sequence A and the integer P will change as follows:
+
, the value of A_P increases by 1;-
, the value of A_P decreases by 1;>
, the value of P increases by 1;<
, the value of P decreases by 1.Takahashi has a string S of length N. Each character in S is one of the symbols +
, -
, >
and <
.
He chose a pair of integers (i, j) such that 1 \leq i \leq j \leq N and ate the symbols that are the i-th, (i+1)-th, ..., j-th characters in S, in this order.
We heard that, after he finished eating, the sequence A became the same as if he had eaten all the symbols in S from first to last.
How many such possible pairs (i, j) are there?
+
, -
, >
or <
.Input is given from Standard Input in the following format:
N S
Print the answer.
5 +>+<-
3
If Takahashi eats all the symbols in S, A_1 = 1 and all other elements would be 0. The pairs (i, j) that leads to the same sequence A are as follows:
5 +>+-<
5
Note that the value of P may be different from the value when Takahashi eats all the symbols in S.
48 -+><<><><><>>>+-<<>->>><<><<-+<>><+<<>+><-+->><<
475