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

const int MAX_N = 1e5 +5;
int N, dp[10];

int main()
{
	ios::sync_with_stdio(0);cin.tie(0);
	
	cin>>N;
	for(int i = 1;i <= N;++i)
	{
		int A;
		cin >> A;
		vector<int>d;
		while(A)
		{
			d.push_back(A % 10);
			A /= 10;
		}
		int y = *d.begin(), x = d.back();
		dp[y] = max(dp[y], dp[x] + 1);
	}
	int len = 0;
	for(int i = 0;i < 10;i++)
	{
		len = max(len,dp[i]);
	}
	cout<<N - len<<endl;
	return 0;            
}