Problem:
We have an H-by-W matrix. Let a_{ij} be the element at the i-th row from the top and j-th column from the left. In this matrix, each a_{ij} is a lowercase English letter.  Snuke is creating another H-by-W matrix, A', by freely rearranging the elements in A. Here, he wants to satisfy the following condition:    * Every row and column in A' can be read as a palindrome.  Determine whether he can create a matrix satisfying the condition.

Incorrect submission (verdict: Wrong Answer):
H, W = [int(x) for x in input().split(" ")]

d = {}

for h in range(H):
    row = input()
    for a in list(row):
        if a in d:
            d[a] += 1
        else:
            d[a] = 1

print(d)

res = False

if H % 2 == 0 and W % 2 == 0:
    for v in d.values():
        if v % 4 != 0:
            res = True
            break
    res = not res

elif H % 2 == 1 and W % 2 == 0:
    cnt4 = (W // 2) * ((H - 1) // 2)
    cnt2 = (W // 2)
    temp4 = 0
    temp2 = 0
    f = True
    for v in d.values():
        if v % 2 != 0:
            f = False
            break

        temp4 += v // 4
        temp2 += 1 if v % 4 != 0 else 0
    
    if f and cnt2 >= temp2 and (cnt2 - temp2) % 2 == 0:
        res = True
elif H % 2 == 0 and W % 2 == 1:
    cnt4 = (H // 2) * ((W - 1) // 2)
    cnt2 = (H // 2)
    temp4 = 0
    temp2 = 0
    f = True
    for v in d.values():
        if v % 2 != 0:
            f = False
            break

        temp4 += v // 4
        temp2 += 1 if v % 4 != 0 else 0
    
    if f and cnt2 >= temp2 and (cnt2 - temp2) % 2 == 0:
        res = True
else:
    cnt4 = ((H - 1) // 2) * ((W - 1) // 2)
    cnt2 = ((H - 1) // 2) + ((W - 1) // 2)
    temp4 = 0
    temp2 = 0
    temp1 = 0

    for v in d.values():
        temp4 += v // 4
        temp2 += (v % 4) // 2
        temp1 += (v % 2)
    
    if temp1 == 1 and cnt2 >= temp2 and (cnt2 - temp2) % 2 == 0:
        res = True

print("Yes" if res else "No")


Fixed, accepted submission:
H, W = [int(x) for x in input().split(" ")]

d = {}

for h in range(H):
    row = input()
    for a in list(row):
        if a in d:
            d[a] += 1
        else:
            d[a] = 1


res = False

if H % 2 == 0 and W % 2 == 0:
    for v in d.values():
        if v % 4 != 0:
            res = True
            break
    res = not res

elif H % 2 == 1 and W % 2 == 0:
    cnt4 = (W // 2) * ((H - 1) // 2)
    cnt2 = (W // 2)
    temp4 = 0
    temp2 = 0
    f = True
    for v in d.values():
        if v % 2 != 0:
            f = False
            break

        temp4 += v // 4
        temp2 += 1 if v % 4 != 0 else 0
    
    if f and cnt2 >= temp2 and (cnt2 - temp2) % 2 == 0:
        res = True
elif H % 2 == 0 and W % 2 == 1:
    cnt4 = (H // 2) * ((W - 1) // 2)
    cnt2 = (H // 2)
    temp4 = 0
    temp2 = 0
    f = True
    for v in d.values():
        if v % 2 != 0:
            f = False
            break

        temp4 += v // 4
        temp2 += 1 if v % 4 != 0 else 0
    
    if f and cnt2 >= temp2 and (cnt2 - temp2) % 2 == 0:
        res = True
else:
    cnt4 = ((H - 1) // 2) * ((W - 1) // 2)
    cnt2 = ((H - 1) // 2) + ((W - 1) // 2)
    temp4 = 0
    temp2 = 0
    temp1 = 0

    for v in d.values():
        temp4 += v // 4
        temp2 += (v % 4) // 2
        temp1 += (v % 2)
    
    if temp1 == 1 and cnt2 >= temp2 and (cnt2 - temp2) % 2 == 0:
        res = True

print("Yes" if res else "No")