/*
 * pun.ccp
 *
 *  Created on: Dec 13, 2022
 *      Author: A.Mulawa
 */

#include <iostream>
#include <string>


int main(int argc, char **argv) {
	int n;
	std::cin >> n;
	int group = n / 10;
	std::string tests;
	std::cin >> tests;

	int res = 0;
	for (int i = 0; i < 10; i++) {
		int pass = 0;
		for (int j = 0; j < group; j++) {
			if (tests[i * group + j] == 'T') {
				pass++;
			}
		}
		if (pass == group) {
			res++;
		}
	}
	std::cout << res;
}