給定一個由 $n$ 個整數 $a_1, a_2, \ldots, a_n$ 組成的序列。你需要求出滿足 $i, j \in \{1, \ldots, n\}$、$i \ne j$ 且 $a_i$ 是 $a_j$ 的因數的有序對 $(i, j)$ 的數量。
輸入第一行包含一個整數 $n$（$1 \le n \le 2\,000\,000$）。第二行包含一個由 $n$ 個整數 $a_1, a_2, \ldots, a_n$（$1 \le a_i \le 2\,000\,000$）組成的序列。
輸出的第一行也是唯一一行應包含一個整數，表示所求有序對的數量。
5 2 4 5 2 6
6
共有 6 個滿足指定性質的有序對：$(1, 2)$、$(1, 4)$、$(1, 5)$、$(4, 1)$、$(4, 2)$、$(4, 5)$。
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