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

#define ll long long

int n,d;
map <int, bool> mm;
int main()
{
	cin>>n;
	for(int i=0;i<n;i++)
	{
		cin>>d;
		mm[d]=1;
	}
	cout<<mm.size()<<endl;
	return 0;	
}