# 
# Solution to Project Euler problem 45
# Copyright (c) Project Nayuki. All rights reserved.
# 
# https://www.nayuki.io/page/project-euler-solutions
# https://github.com/nayuki/Project-Euler-solutions
# 


def compute():
	i = 286
	j = 166
	k = 144
	while True:
		triangle = i * (i + 1) // 2
		pentagon = j * (j * 3 - 1) // 2
		hexagon  = k * (k * 2 - 1)
		minimum = min(triangle, pentagon, hexagon)
		if minimum == max(triangle, pentagon, hexagon):
			return str(triangle)
		if minimum == triangle: i += 1
		if minimum == pentagon: j += 1
		if minimum == hexagon : k += 1


if __name__ == "__main__":
	print(compute())