时间限制：C/C++/Rust/Pascal 1秒，其他语言2秒
空间限制：C/C++/Rust/Pascal 256 M，其他语言512 M
64bit IO Format: %lld
空间限制：C/C++/Rust/Pascal 256 M，其他语言512 M
64bit IO Format: %lld
题目描述
Walk Alone has a string, and he wants you to count the number of consecutive 'fyt' in the string.
For example, the answer to 'ffyt' is
since the second to the fourth character forms a consecutive 'fyt', while 'ffyytt' has no 'fyt' as its substring.
For example, the answer to 'ffyt' is
输入描述:
The first line contains an integer, indicating the length of the string.
The second line contains a single string consisting of three characters 'f', 'y', and 't', representing the string.
输出描述:
Output a single integer indicating the number of consecutive 'fyt' in the input string.