# Arup Guha
# 12/9/2025
# Solution to 2025 UCF HS Online D2 Problem C: Echoing Events

# Get the input.
n = int(input())

# Put stuff here.
stuff = set()

# Initialize our variables.
found = False
item = "NO ECHOES SPOTTED"

# Just read through everything.
for i in range(n):

    # Get this item.
    cur = input().strip()

    # Condition for our first repeat.
    if not found and cur in stuff:
        item = cur
        found = True

    # Add item to the list.
    stuff.add(cur)

# Ta da!
print(item)