畀你一個由 $n$ 個整數 $a_1, a_2, \ldots, a_n$ 組成嘅序列。你要搵出有幾多個有序對 $(i, j)$ 滿足 $i, j \in \{1, \ldots, n\}$、$i \ne j$，而且 $a_i$ 係 $a_j$ 嘅因數。
輸入第一行有一個整數 $n$（$1 \le n \le 2\,000\,000$）。第二行有一個由 $n$ 個整數 $a_1, a_2, \ldots, a_n$（$1 \le a_i \le 2\,000\,000$）組成嘅序列。
輸出第一行亦都係唯一一行，要有一個整數，表示要搵嘅有序對數量。
5 2 4 5 2 6
6
有 6 個有序對符合指定條件：$(1, 2)$、$(1, 4)$、$(1, 5)$、$(4, 1)$、$(4, 2)$、$(4, 5)$。
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