CF1295C.Obtain The String

You are given two strings $s$ and $t$ consisting of lowercase Latin letters. Also you have a string $z$ which is initially empty. You want string $z$ to be equal to string $t$. You can perform the following operation to achieve this: append any subsequence of $s$ at the end of string $z$. A subsequence is a sequence that can be derived from the given sequence by deleting zero or more elements without changing the order of the remaining elements. For example, if $z = ac$, $s = abcde$, you may turn $z$ into following strings in one operation:

1. $z = acace$ (if we choose subsequence $ace$);
2. $z = acbcd$ (if we choose subsequence $bcd$);
3. $z = acbce$ (if we choose subsequence $bce$).

Note that after this operation string $s$ doesn't change.

Calculate the minimum number of such operations to turn string $z$ into string $t$.

给你两个由小写拉丁字母组成的字符串 $s$ 和 $t$。此外，你还有一个初始为空的字符串 $z$。你的目标是使字符串 $z$ 等于字符串 $t$。你可以执行以下操作来实现这一目标：将 $s$ 的任意一个子序列追加到字符串 $z$ 的末尾。子序列是指从给定序列中删除零个或多个元素（不改变剩余元素的相对顺序）所得到的序列。例如，若 $z = ac$，$s = abcde$，则在一次操作中，你可以将 $z$ 变为如下字符串之一：

1. $z = acace$（若选择子序列 $ace$）；
2. $z = acbcd$（若选择子序列 $bcd$）；
3. $z = acbce$（若选择子序列 $bce$）。

注意：执行该操作后，字符串 $s$ 本身不会发生变化。

请计算将字符串 $z$ 变为字符串 $t$ 所需的最少操作次数。

The first line contains the integer $T$ ($1 \le T \le 100$) — the number of test cases.

The first line of each testcase contains one string $s$ ($1 \le |s| \le 10^5$) consisting of lowercase Latin letters.

The second line of each testcase contains one string $t$ ($1 \le |t| \le 10^5$) consisting of lowercase Latin letters.

It is guaranteed that the total length of all strings $s$ and $t$ in the input does not exceed $2 \cdot 10^5$.

第一行包含一个整数 $T$（$1 \le T \le 100$）—— 表示测试用例的数量。

每个测试用例的第一行包含一个字符串 $s$（$1 \le |s| \le 10^5$），由小写拉丁字母组成。

每个测试用例的第二行包含一个字符串 $t$（$1 \le |t| \le 10^5$），由小写拉丁字母组成。

保证输入中所有字符串 $s$ 和 $t$ 的总长度不超过 $2 \cdot 10^5$。

For each testcase, print one integer — the minimum number of operations to turn string $z$ into string $t$. If it's impossible print $-1$.

对于每个测试用例，输出一个整数——将字符串 $z$ 变为字符串 $t$ 所需的最少操作次数。如果无法实现，则输出 $-1$。