#include <iostream>
#include <vector>
#include <set>
#define rep(i, l, n) for (int i = (l); i < (n); i++)
#define itrep(itr, st) for(auto itr = st.begin(); itr != st.end(); itr++)
using namespace std;
template <class T>	using V = vector<T>;


int main(void) {
	int N, K;	cin >> N >> K;
	set<string> st = {};
	rep(i, 0, N) {
		string s;	cin >> s;
		st.insert(s);
	}

	set<string> visited = {};
	itrep(itr, st) {
		string sv = *itr;
		if (visited.find(sv) != visited.end()) {
			continue;
		}
		V<string> stk = { sv };
		while (stk.empty() == false) {
			string v = stk[stk.size() - 1];
			stk.pop_back();
			rep(i, 0, K) {
				if (v[i] == 'D') {
					continue;
				}
				string nv = v;	nv[i]++;
				if (visited.find(nv) != visited.end()) {
					continue;
				}
				visited.insert(nv);
				stk.push_back(nv);
			}
		}
	}

	int ans = 0;
	itrep(itr, st) {
		if (visited.find(*itr) == visited.end()) {
			continue;
		}
		ans++;
	}
	cout << ans << endl;

	return 0;
}