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Time Limit: 4.0 s Memory Limit: 1024 MB Total points: 100 Hackable ✓

#17959. 石仔 2

Statistics

$N$ 粒石仔由 $1$ 至 $N$ 編號,按編號遞增嘅次序排成一行。每粒石仔都係白色或者黑色。第 $i$ 粒石仔嘅重量係 $A_i$。

你會逐粒移走石仔,直到所有石仔都移走為止。

移走一粒石仔嗰陣,如果佢唔係剩低所有石仔之中最左邊或者最右邊嗰粒,而且同佢相鄰嘅兩粒石仔顏色都同佢唔同,你嘅分數就會加上被移走嗰粒石仔嘅重量。如果兩粒石仔之間冇其他石仔,就叫做相鄰。

移走晒所有石仔一共有 $N!$ 種可能嘅方法。計算每種方法所得分數嘅總和,再對 $998\,244\,353$ 取模。

輸入

第一行有一個整數 $N$($1 \le N \le 300\,000$)。

第二行有一條長度為 $N$ 嘅字串 $S$,每個字元都係 B 或者 W。如果第 $i$ 粒石仔係黑色,$S$ 嘅第 $i$ 個字元 $S_i$ 就係 B;否則 $S_i$ 係 W,而第 $i$ 粒石仔係白色。

第三行有 $N$ 個整數 $A_1,A_2,\ldots,A_N$($1 \le A_i \le 10^9$)。$A_i$ 代表第 $i$ 粒石仔嘅重量。

輸出

輸出所有移走石仔方法所得分數嘅總和,再對 $998\,244\,353$ 取模。

例子

輸入 1

4
WBWB
6 4 5 3

輸出 1

72

輸入 2

8
WBBWBWBB
6 4 8 2 5 3 1 5

輸出 2

218304

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