Problem:
Score : 700 points

Problem Statement

There are N cats.
We number them from 1 through N.

Each of the cats wears a hat.
Cat i says: "there are exactly a_i different colors among the N - 1 hats worn by the cats except me."

Determine whether there exists a sequence of colors of the hats that is consistent with the remarks of the cats.

Constraints

2 ≤ N ≤ 10^5

1 ≤ a_i ≤ N-1

Input

Input is given from Standard Input in the following format:

N
a_1 a_2 ... a_N

Output

Print Yes if there exists a sequence of colors of the hats that is consistent with the remarks of the cats; print No otherwise.

Sample Input 1

3
1 2 2

Sample Output 1

Yes

For example, if cat 1, 2 and 3 wears red, blue and blue hats, respectively, it is consistent with the remarks of the cats.

Sample Input 2

3
1 1 2

Sample Output 2

No

From the remark of cat 1, we can see that cat 2 and 3 wear hats of the same color.
Also, from the remark of cat 2, we can see that cat 1 and 3 wear hats of the same color.
Therefore, cat 1 and 2 wear hats of the same color, which contradicts the remark of cat 3.

Sample Input 3

5
4 3 4 3 4

Sample Output 3

No

Sample Input 4

3
2 2 2

Sample Output 4

Yes

Sample Input 5

4
2 2 2 2

Sample Output 5

Yes

Sample Input 6

5
3 3 3 3 3

Sample Output 6

No

Solution in Python (3.4.3) (judge verdict: Wrong Answer)

from collections import Counter

N = int(input())
A = list(map(int, input().split()))

cntA = Counter(A)
cntA = list(cntA.items())
cntA.sort()

if len(cntA) >= 3:
    print('No')
elif len(cntA) == 1:
    if cntA[0][0] == N - 1:
        print('Yes')
    elif N // 2 >= cntA[0][0]:
        print('Yes')
    else:
        print('No')
elif len(cntA) == 2:
    if cntA[0][0] + 1 == cntA[1][0]:
        if N >= cntA[0][1] + (cntA[1][0] - cntA[0][1]) * 2:
            print('Yes')
        else:
            print('No')
    else:
        print('No')