C++ :

#include<bits/stdc++.h>
using namespace std;
int k,n,a[10],ans;
string s; 
int main()
{
	cin>>k>>n;
	while(n--)
	{
		cin>>s;
		int x=s[0]-'0';
		a[x]++;
	}
	for(int i=0;i<=9;i++)
	{
		int tmp=a[i]/k;
		if(a[i]%k!=0) tmp++;
		ans+=tmp;		
	}
	cout<<ans+2;
    return 0;
}