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

before=A[0]
ans=0 if n%2==0 else 1
flag=True
for i in range(1,n):
    if before!=A[i]:
        if flag:
            ans+=1
            flag=False
        else:
            flag=True
    else:
        ans+=1
print(ans)