Count the lines of input files
描述The input file will contain an unknown number of lines with at most 1000 characters on each line. All the characters will be printable ASCII characters.
输入
The input file contains some lines.
Note that the input file will always exist, but may be empty.
输出
The number of lines in the input file.
样例输入
one
and two
three
样例输出
3
高手们这个该怎么做啊？？没思路厄
