n = int(input())
ls = [0]+list(input().split())
dp = [[0]*15 for i in range(n+5)]
for i in range(1,n+1):
    for j in range(10):
        dp[i][j] = dp[i-1][j]+1

    final = int(ls[i][-1])
    first = int(ls[i][0])
    dp[i][final] = min(dp[i-1][first],dp[i][final])
    
    
ans = float('inf')
for i in range(10):
    ans = min(ans,dp[n][i])
print(ans)