import sys input = sys.stdin.readline n, k = map(int, input().split()) A = list(map(int, input().split())) S = list(input()) mod = 10 ** 9 + 7 def compress(A): XS = list(set(A)) XS.sort() return len(XS), {e: i for i, e in enumerate(XS)}, {i: e for i, e in enumerate(XS)} nagasa, valtoidx, idxtoval = compress(A) class SegmentTree: # SEG木は1-index # Aに関しては0-index def __init__(self, n, ele, func): # Aは0-idx self.n = n self.ele = ele self.func = func self.num = 2 ** ((self.n - 1).bit_length()) self.SEG = [self.ele] * (2 * self.num) def search(self, idx): return self.SEG[idx + self.num] def initialize(self, A): for i in range(self.n): self.SEG[i + self.num] = A[i] for i in range(self.num - 1, 0, -1): self.SEG[i] = self.func(self.SEG[2 * i], self.SEG[2 * i + 1]) # 1点更新 def set(self, idx, val): idx += self.num self.SEG[idx] += val idx //= 2 while idx: self.SEG[idx] = self.func(self.SEG[2 * idx], self.SEG[2 * idx + 1]) idx //= 2 # 区間取得 def query(self, left, right): # 開区間 resleft = self.ele resright = self.ele left += self.num right += self.num while right - left > 0: if left % 2 == 1: resleft = self.func(resleft, self.SEG[left]) left += 1 if right % 2 == 1: right -= 1 resright = self.func(self.SEG[right], resright) left //= 2 right //= 2 return self.func(resleft, resright) def debug(self): print("Segmant") for i in range((self.n - 1).bit_length() + 1): print(self.SEG[1 << i : 1 << (i + 1)]) # 初期条件 def func(a, b): return (a + b) % mod ele = 0 # i個目まで使って、j個の不等号を満たしている数 # dp = [[0] * (k + 1) for _ in range(n + 1)] pre = [SegmentTree(nagasa + 1, ele, func) for _ in range(k + 1)] for i in range(n): ni = i + 1 a = A[i] idx = valtoidx[a] pre[0].set(idx, 1) rem = n - i for nj in range(1, k + 1)[::-1]: j = nj - 1 if S[j] == ">": val = pre[j].query(idx + 1, nagasa + 1) else: val = pre[j].query(0, idx) pre[nj].set(idx, val) # print("i", i, file=sys.stderr) # pre[1].debug() print(pre[k].query(0, nagasa + 1))