#include "bits/stdc++.h"
#include<unordered_map>
#include<unordered_set>
#pragma warning(disable:4996)
using namespace std;
using ld = long double;
const ld eps = 1e-9;

//// < "d:\d_download\visual studio 2015\projects\programing_contest_c++\debug\a.txt" > "d:\d_download\visual studio 2015\projects\programing_contest_c++\debug\b.txt"


int main() {

	int N, K; cin >> N >> K;
	vector<int> nums(26);
	for (int i = 0; i < 26; ++i)nums[i] = 0;
	for (int i = 0; i < N; ++i) {

		string st; cin >> st;
		nums[st[0] - 'A']++;
	}
	int ans = 0;
	while (1) {
		sort(nums.begin(), nums.end(), greater<int>());
		bool ok = true;
		for (int i = 0; i <K; ++i) {
			if (nums[i])nums[i]--;
			else ok = false;
		}
		if (ok)ans++;
		else break;

	}
	cout << ans << endl;
	return 0;
}