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

const int MAXN = 100005;

int n, a[MAXN];

int main()
{
	ios::sync_with_stdio(false);
	cin >> n;
	for (int i = 1; i <= n; i++) cin >> a[i];
	auto solve = [](int tot) {
		int cnt = 0;
		for (int i = 1; i <= n; i++) {
			if (a[i] != tot && a[i] != tot-1) return false;
			if (a[i] == tot-1) cnt++;
		}
		if (tot < cnt) return false;
		int col = tot-cnt, cat = n-cnt;
		if (cat && col == 0) return false;
		return cat >= 2*col;
	};
	if (solve(a[1]) || solve(a[1]+1)) puts("Yes");
	else puts("No");
	return 0;
}
