n=int(input())
l=input().split()
a=[]
j,num=1,0
for i in range(n-1):
    if l[i]==l[i+1]:
        j+=1
    else:
        a.append(j)
        j=1
        num+=1
a.append(j)
num+=1
s=a[0]
m=0
for i in range(num-1):
    x,y=a[i],a[i+1]
    if x==1:
        if m==1:
            s+=y
            m=0
        elif y==1:
            m=1
        else:
            s+=y-1
    elif y==1:
        m=1
    else:
        s+=y-1
print(s)