Untitled

def calculate_value(s):
    # If there are digits in the string, concatenate them and convert to an integer.
    digits = ''.join(filter(str.isdigit, s))
    if digits:
        return int(digits)
    # If there are no digits, return the length of the string.
    return len(s)

def max_product_of_values(arr):
    n = len(arr)
    max_product = 0

    # Iterate through the array to calculate values and find the maximum product.
    for i in range(n):
        for j in range(i + 1, n):
            product = calculate_value(arr[i]) * calculate_value(arr[j])
            max_product = max(max_product, product)

    return max_product

# Input
n = int(input())
arr = input().split()

# Calculate and print the maximum product of values
result = max_product_of_values(arr)
print(result)