CF44A.Indian Summer

Indian summer is such a beautiful time of the year! A girl named Alyona is walking in the forest and picking a bouquet from fallen leaves. Alyona is very choosy — she doesn't take a leaf if it matches the color and the species of the tree of one of the leaves she already has. Find out how many leaves Alyona has picked.

印度夏日是一年中如此美好的时节！一位名叫阿廖娜的女孩正在森林中漫步，采摘落在地上的树叶来制作花束。阿廖娜非常挑剔——如果某片叶子的颜色和树种与她已有的某片叶子完全相同，她就不会采摘它。请计算阿廖娜一共采摘了多少片树叶。

The first line contains an integer n (1 ≤ n ≤ 100) — the number of leaves Alyona has found. The next n lines contain the leaves' descriptions. Each leaf is characterized by the species of the tree it has fallen from and by the color. The species of the trees and colors are given in names, consisting of no more than 10 lowercase Latin letters. A name can not be an empty string. The species of a tree and the color are given in each line separated by a space.

第一行包含一个整数 $n$（$1 \leq n \leq 100$）—— Alyona 找到的树叶数量。接下来的 $n$ 行描述了这些树叶。每片树叶由其脱落的树种及其颜色表征。树种名称与颜色名称均由至多 10 个小写拉丁字母组成，且不能为空字符串。每行中，树种名称与颜色名称以空格分隔。

Output the single number — the number of Alyona's leaves.

输出单个数字——Alyona 的叶子数量。