#include <iostream>

template<typename X>
X input() {
	X value;
	std::cin >> value;
	return value;
}

int main() {
	int x = input<int>();
	int x3 = x * x * x;
	std::cout << x3 << std::endl;

	return 0;
}
#include <bits/stdc++.h>
using namespace std;
#define REP(i, a, b) for (int i = (int)(a); i < (int)(b); i++)
#define rep(i, n) REP(i, 0, n)
#define rrep(i, n) for (int i = (int)(n-1); i >= 0; i--)
#define sz(x) int(x.size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define INF 2e9
#define LINF 1e18
#define mod 1000000007
template<class T> inline bool chmax(T &a, const T &b) { if (a < b) { a = b; return 1; } return 0; }
template<class T> inline bool chmin(T &a, const T &b) { if (a > b) { a = b; return 1; } return 0; }
typedef long long ll;
typedef pair<int, int> P;
int dx[4] = {1,0,-1,0};
int dy[4] = {0,1,0,-1};


int main() {
    int n; cin >> n;
    set<int> st;
    rep(i,n) {
        int a; cin >> a;
        st.insert(a);
    }
    if (sz(st) == n) cout << "YES" << endl;
    else cout << "NO" << endl;
}   