## https://yukicoder.me/problems/no/1912


def main():
    N, M = map(int, input().split())
    V = list(map(int, input().split()))
    S = []
    for _ in range(N):
        S.append(input())

    # 各Nについて使える箱をbitmask化する
    usable_box_set = []
    for i in range(N):
        bit = 0
        s = S[i]
        for m in range(M):
            if s[m] == "o":
                bit |= (1 << m)
        usable_box_set.append(bit)

    # 箱に入れた時の価値を最大にしてく
    used = 0    
    answer = 0
    for _ in range(M):
        values = []
        for i in range(M):
            if used & (1 << i) > 0:
                continue

            total_value = 0
            for j in range(N):
                bit = usable_box_set[j]
                v = V[j]
                if bit & (1 << i) > 0 and bit & used == 0:
                    total_value += v
            values.append((i, total_value))
        values.sort(key=lambda x: x[1],reverse=True)
        index, v = values[0]
        used |= (1 << index)
        answer += v ** 2
    print(answer)
        














if __name__ == "__main__":
    main()