n=input()
x=sorted(list(map(int,input().split(" "))))
while True:
    try:
        f=False
        for i in range(len(x)):
            x1,x2=x[i],x[i+1]
            if (x1+x2)%2==0 or (x1-1 in x and x2+1 in x):
                continue
            x.remove(x1)
            x.remove(x2)
            f=True
        if f==False:
            break
    except IndexError:
        if len(x)==1:
            break
        continue
print(len(x))