发布时间: 2018年12月8日 20:11 最后更新: 2018年12月8日 20:12 时间限制: 1000ms 内存限制: 512M
Given an integer $n$, we suppose that $a, b$ are independent and uniform random integers on the interval $[1,n]$.
Calculate the probability where a and b are coprime.
Note: two integers are said to be coprime if the only positive factor that divides both of them is 1.
A single line with the integer $n(2 \le n \le 100)$.
Display the most simple fraction(which can be represented in the form of $p/q$, where p and q are coprime), representing the probability.
On 3 cases a and b are coprime that:
$a = 1, b = 1;$
$a = 1, b = 2;$
$a = 2, b = 1$
while the total number of cases is 4.