import sys
sys.setrecursionlimit(1000000000)

#
# Solution Template for IGM
# 
# Australian Informatics Olympiad 2026
# 
# 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 delegates.
N = 0
# A contains the delegates' importance values. The list starts from 0.
A = []

# Read the number of delegates and their importance values.
N = int(input().strip())
A = list(map(int, input().strip().split()))

# TODO: Determine whether a valid starting delegate exists. Output YES or NO.
# An example YES output is shown below.
print("YES")