#include<bits/stdc++.h>
using namespace std;
int main(){
    int n;
    cin >> n;
    int a[n];
    for(int i = 0; i < n; i++) cin >> a[i];
    for(int i = 0; i < n - 1; i++){
        if(a[i] != a[i+1]) {
            cout << "No" << endl;
            return 0;
        }
    }
    cout << "Yes";
    return 0;
}

#include<bits/stdc++.h>
using namespace std;
#define int long long
signed main()
{
	int n;cin>>n;
	int x;cin>>x;
	for(int i=2;i<=n;i++)
	{
		int y;cin>>y;
		if(y!=x){cout<<"No";return 0;}
	}
	cout<<"Yes";
	return 0;
}