Geometric progression with the first element a and common ratio b is a sequence of numbers a, ab, ab 2, ab 3, .... You are given n integer geometric progressions. Your task is to find the smallest integer x , that is the element of all the given progressions, or else state that such integer does not exist.
输入描述:
The first line contains integer (1 ≤ n ≤ 100) — the number of geometric progressions. Next n lines contain pairs of integers a, b (1 ≤ a, b ≤ 109), that are the first element and the common ratio of the corresponding geometric progression.


输出描述:
If the intersection of all progressions is empty, then print - 1, otherwise print the remainder of the minimal positive integer number belonging to all progressions modulo 1000000007 (109 + 7).
示例1

输入

2<br />2 2<br />4 1<br />2<br />2 2<br />3 3<br />

输出

4<br />-1<br />

备注:
In the second sample test one of the progressions contains only powers of two, the other one contains only powers of three.
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