N =input()
L=[]
first = raw_input()
for i in range(0,N):
    split_first = first.split()
    L.append(int(split_first[i]))
    
LA,LB = [],[L[0]]
for i in range(0,N-1):
    if L[i] == L[i+1]:
        LA.append(L[i+1])
    else:
        LB.append(L[i+1])
LA= set(LA)
print len(LB)-len(LA)