import sys
sys.setrecursionlimit(1000000000)

#
# Solution Template for Composing Pyramids
# 
# Australian Informatics Olympiad 2022
# 
# This file is provided to assist with reading of input and writing of output 
# for the problem. You may modify this file however you wish, or
# you may choose not to use this file at all.
#

# N is the number of keys in the sequence.
N = 0

# P contains the sequence of keys.
P = []

answer = 0

# Read the value of N.
N = int(input().strip())

# Read the sequence of keys.
P = list(map(int, input().strip().split()))

# TODO: This is where you should compute your solution. Store the minimum
# number of keys you need to remove from the sequence into the variable answer.

# Write the answer.
print(answer)