题解 | 合唱队

import sys

n = int(input())
lst = input().split()
h = [int(x) for x in lst]  # 简化输入处理

def max_chorus_length(heights):
    n = len(heights)
    if n <= 2:
        return n  # 人数不足时无需调整
    
    # 计算每个位置向左的最长递增子序列长度
    left = [1] * n
    for i in range(n):
        for j in range(i):
            if heights[j] < heights[i]:  # 严格递增
                left[i] = max(left[i], left[j] + 1)
    
    # 计算每个位置向右的最长递减子序列长度
    right = [1] * n
    for i in range(n-1, -1, -1):
        for j in range(i+1, n):
            if heights[j] < heights[i]:  # 严格递减
                right[i] = max(right[i],right[j] + 1)
    
    # 找到中间点i，使得left[i]+right[i]-1最大（减1是因为i被重复计算）
    max_length = 0
    for i in range(n):
        max_length = max(max_length, left[i] + right[i] - 1)
    
    return max_length

# 计算最少出列人数
max_keep = max_chorus_length(h)
min_leave = n - max_keep
print(min_leave)