#include <iostream>
#include <vector>
using namespace std;

int main() {
	vector<bool> a(202, false);
    int n, diffNum, curVal;
    cin >> n;
    diffNum = n;
    for(int i = 0; i < n; i++) {
        cin >> curVal;
        if(a[curVal + 100]) diffNum--;
        else a[curVal + 100] = true;
    }
    cout << diffNum << endl;
}