One day Kefa found n baloons. For convenience, we denote color of i-th baloon as s_{i} — lowercase letter of the Latin alphabet. Also Kefa has k friends. Friend will be upset, If he get two baloons of the same color. Kefa want to give out all baloons to his friends. Help Kefa to find out, can he give out all his baloons, such that no one of his friens will be upset — print «YES», if he can, and «NO», otherwise. Note, that Kefa's friend will not upset, if he doesn't get baloons at all.


-----Input-----

The first line contains two integers n and k (1 ≤ n, k ≤ 100) — the number of baloons and friends.

Next line contains string s — colors of baloons.


-----Output-----

Answer to the task — «YES» or «NO» in a single line.

You can choose the case (lower or upper) for each letter arbitrary.


-----Examples-----
Input
4 2
aabb

Output
YES

Input
6 3
aacaab

Output
NO



-----Note-----

In the first sample Kefa can give 1-st and 3-rd baloon to the first friend, and 2-nd and 4-th to the second.

In the second sample Kefa needs to give to all his friends baloons of color a, but one baloon will stay, thats why answer is «NO».

Difficulty: interview

Starter code:

Solutions:
alpha = [chr(ord('a')+i) for i in range(26)]
n,k = list(map(int,input().split()))
s = input()
arr = [s.count(alpha[i]) for i in range(26)]

print('YES' if max(arr) <= k else 'NO')


n, k = map(int, input().split())
s = input()
d = {}

for el in s:
    if el in d:
        d[el] += 1
    else:
        d[el] = 1

for value in d.values():
    if value > k:
        print('NO')
        return

print('YES')

def list_input():
    return list(map(int,input().split()))
def map_input():
    return map(int,input().split())
def map_string():
    return input().split()
    
n,k = map_input()
s = input()
ans = 0
for i in s:
    ans = max(ans,s.count(i))
if ans <= k:
    print("YES")
else:
    print("NO")

n,k=list(map(int,input().split()))
s=str(input())
b=0
ip=[0 for i in range(256)]
for i in s:
   ip[ord(i)-97]+=1
for i in ip:
   if i>k:
      print("NO")
      b=1
      break
if b==0:
   print("YES")


n,k = [int(i) for i in input().split()]
s = input()

for i in range(ord('a'), ord('z') + 1):
    x = 0
    for j in s:
        if ord(j) == i:
            x += 1
    if x > k:
        print('NO')
        return

print('YES')


n, k = map(int, input().split())
s = input()
d = dict()
for i in s:
    d[i] = d.get(i, 0) + 1
    if d[i] > k:
        print('NO')
        return
print('YES')

import math 
def __starting_point():
	n,k = list(map(int,input().split()))
	s = input()
	s = list(s)
	ls = set(s)
	flag = 1
	for i in ls:
		if s.count(i)>k:
			flag = 0
	if flag :
		print("YES")
	else:
		print("NO")


__starting_point()

n, k = map(int, input().split())
s = input()
f = True
for i in range(n):
    if s.count(s[i]) > k:
        f = False
if f:
    print("YES")
else:
    print("NO")

n, k = map(int, input().split())
ns = {}
for c in input():
    if c in ns.keys():
        ns[c] += 1
    else:
        ns[c] = 1
for a in ns.values():
    if a > k:
        print("NO")
        break
else:
    print("YES")

from collections import Counter
n, k = [int(i) for i in input().split()]
s = input()
C = Counter(s)
for c in C:
    if(C[c] > k):
        print("NO")
        break
else:
    print("YES")


from collections import Counter

n, k = [int(v) for v in input().split()]
s = input().strip()

cnt = Counter(s)
print(["NO", "YES"][all([v <= k for v in cnt.values()])])

n, k = map(int, input().split())
s = input()
flag = True
for i in range(n):
    if s.count(s[i]) > k:
        flag = False
if flag:
    print("YES")
else:
    print("NO")

n,m=list(map(int,input().split()))
s=input()
count={}
for val in s:	
	if(val not in count):
		count[val]=0
	count[val]+=1
flag=0
for item in count:
	if(count[item]>m):
		flag=1
		break
if(flag==0):
	print("YES")
else:
	print("NO")

a, b = map(int, input().split())
s = input()
letters = {}
for x in s:
    if not x in letters:
        letters[x] = 0
    letters[x] += 1
for x in letters.values():
    if x > b:
        print("NO")
        break
else:
    print("YES")

n, k = map(int, input().split())

d = dict()
arr = input()
for i in range(len(arr)):
    if arr[i] in d:
        d[arr[i]] += 1
        if d[arr[i]] > k:
            print('NO')
            break
    else:
        d[arr[i]] = 1
else:
    print('YES')

n,k = map(int,input().split())
arr = input()
maxi = 0

for i in range(26):
    temp = arr.count(chr(ord('a')+i))
    if(temp>maxi):
        maxi = temp
if(maxi>k):
    print("NO")
else:
    print("YES")

n, k = list(map(int,input().split()))
st = input()
a = [0] * 28
for i in range(len(st)):
	a[ord(st[i]) - 97] += 1
if max(a) <= k: print('YES')
else: print('NO')


from collections import Counter as cc
n,m=list(map(int,input().split()))
s=[i for i in input()]
c=cc(s)
if max(c.values())>m:
    print("NO")
else:
    print("YES")


n, k = [int(i) for i in input().split()]
s = input()
m = [0] * 1000
for c in s:
    m[ord(c)] += 1
if max(m) > k:
    print("NO")
else:
    print("YES")


n, k = list(map(int, input().split()))
s = list(input())

cnt = {}
for c in s:
    if c in cnt:
        cnt[c] += 1
    else:
        cnt[c] = 1
ans = "YES"
for v in list(cnt.values()):
    if k < v:
        ans = "NO"
        break
print(ans)


from collections import Counter

balls_nr, friends_nr = (int(x) for x in input().split())
ball_idx___color = input()
if max(Counter(ball_idx___color).values()) > friends_nr:
    print('NO')
else:
    print('YES')



from collections import Counter

n, k = list(map(int, input().split()))
colors = input()

d = Counter(colors)

for color, i in list(d.items()):
    if i > k:
        print('NO')
        break
else:
    print('YES')


import sys

input = sys.stdin.readline

alpha = 'abcdefghijklmnopqrstuvwxyz'

count = {}

for i in alpha:
    count[i] = 0

n, f = list(map(int,input().split()))

balls = list(input().strip('\n'))

for i in range(n):
    count[balls[i]] += 1

max = 0

for i in alpha:
    if count[i] > max:
        max = count[i]

if (max > f):
    print("NO")
else:
    print("YES")


n,k = list(map(int,input().split()))
data = input()
a={}
for i in data:
    if i in a:
        a[i]+=1
    else:
        a[i]=1
for i in list(a.values()):
    if i>k:
        print('NO')
        break
else:
    print('YES')


n, k = list(map(int, input().split()))
s = input()
c = dict()
for x in s:
    if not x in c:
        c[x] = 1
    else:
        c[x] += 1

no = False
for x in c:
    if c[x] > k:
        print("NO")
        no = True
        break
if not no:
    print("YES")