#include <bits/stdc++.h>
using namespace std;

#define FOR(i, a, b) for(int i = (a); i < (b); i++)
#define RFOR(i, a, b) for(int i = (a) - 1; i >= (b); i--)
#define SZ(a) int(a.size())
#define ALL(a) a.begin(), a.end()
#define PB push_back
#define MP make_pair
#define F first
#define S second

typedef long long LL;
typedef vector<int> VI;
typedef vector<LL> VL;
typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;
typedef double db;


VI shifts = {0, 2, 4, 5, 7, 9, 11, 12};
vector<string> notes = {"Do", "Do#", "Re", "Re#", "Mi", "Fa", "Fa#", "Sol", "Sol#", "La", "La#", "Si"};


int basicNote[12];



int main()
{
	ios::sync_with_stdio(0); 
	cin.tie(0);
	
	FOR(i, 0, 12)
	{
		for(int sh : shifts)
			basicNote[(i + sh) % 12] |= 1 << i;
	}
	
	int n;
	cin >> n;
	
	VI input(n);
	FOR(i, 0, n)
	{
		string s;
		cin >> s;
		int id = -1;
		FOR(j, 0, 12)
			if(notes[j] == s)
				id = j;
		assert(id != -1);
		input[i] = id;
	}
	
	int ans = n;
	FOR(note, 0, 12)
	{
		int l = 0;
		while(l < n && basicNote[input[l]] & (1 << note))
			l++;
		if(l == n)
		{
			ans = 1;
			break;
		}
		int r = n - 1;
		while(r >= 0 && basicNote[input[r]] & (1 << note))
			r--;
		
		
		int mask = 0;
		int cur = 0;
		
		FOR(i, l, r + 1)
		{
			int id = input[i];
			
			mask = mask & basicNote[id];
			if(mask == 0)
			{
				cur++;
				mask = basicNote[id];
			}		
		}
		ans = min(ans, cur + 1);
	}
	cout << ans << "\n";
	return 0;
}