Problem:
Score : 100 points

Problem Statement

Let N be a positive integer.
You are given a string s of length N - 1, consisting of < and >.

Find the number of permutations (p_1, p_2, \ldots, p_N) of (1, 2, \ldots, N) that satisfy the following condition, modulo 10^9 + 7:

For each i (1 \leq i \leq N - 1), p_i < p_{i + 1} if the i-th character in s is <, and p_i > p_{i + 1} if the i-th character in s is >.

Constraints

N is an integer.

2 \leq N \leq 3000

s is a string of length N - 1.

s consists of < and >.

Input

Input is given from Standard Input in the following format:

N
s

Output

Print the number of permutations that satisfy the condition, modulo 10^9 + 7.

Sample Input 1

4
<><

Sample Output 1

5

There are five permutations that satisfy the condition, as follows:

(1, 3, 2, 4)

(1, 4, 2, 3)

(2, 3, 1, 4)

(2, 4, 1, 3)

(3, 4, 1, 2)

Sample Input 2

5
<<<<

Sample Output 2

1

There is one permutation that satisfies the condition, as follows:

(1, 2, 3, 4, 5)

Sample Input 3

20
>>>><>>><>><>>><<>>

Sample Output 3

217136290

Be sure to print the number modulo 10^9 + 7.

Solution in PyPy3 (2.4.0) (judge verdict: Accepted)

# coding: utf-8
# Your code here!
n=int(input())
s=input()
MOD = 10**9+7

dp = [1]*n

for i,c in enumerate(s):
    if c == "<":
        ssum = sum(dp[1:n-i])
        ssum %= MOD
        for j in range(n-i-1):
            dp[j] = ssum
            ssum -= dp[j+1]
            ssum %= MOD

    else:
        ssum = dp[0]
        for j in range(n-i-1):
            dp[j] = ssum
            ssum += dp[j+1]
            ssum %= MOD

#    print(dp)


print(dp[0])