/*
TASK:man
LANG:C++
*/
#include <iostream>
using namespace std;
int sort1(int,int);
int sort1(int a[10000],int n)
{
    int tmp;
    for (int i=0;i<n;i++)
    {
        for (int j=0;j<n-1;j++)
        {
            if (a[j]>a[j+1])
            {
                tmp=a[j];
                a[j]=a[j+1];
                a[j+1]=tmp; 
            }
            
        } 
    }
}
int main()
{

    int m,br=-1;
    int b[10000],c[10000]; 
    cin >> m;
    for (int q=0;q<m*2;q+=2)
    cin >> b[q] >> b[q+1];
    sort1(b,m*2);
    for (int i=0;i<m*2;i++)
    if (b[i]!=b[i+1]) br++;
    cout << br;
    cout << endl;
return 0;
}
