import os
import sys

def tri_generator(start=0):
    idx = start
    while True:
        yield 0.5*idx*float(idx+1)
        idx += 1

def pent_generator(start=0):
    idx = start
    while True:
        yield 0.5*idx*float(3*idx-1)
        idx += 1

def hex_generator(start=0):
    idx = start
    while True:
        yield idx*float(2*idx-1)
        idx += 1

def main():
    #from time import sleep
    tri_idx = 245 + 1
    pent_idx = 165 + 1
    hex_idx = 143 + 1
    #tri_idx = pent_idx = hex_idx = 2
    tri_gen = tri_generator(tri_idx)
    pent_gen = pent_generator(pent_idx)
    hex_gen = hex_generator(hex_idx)

    t = tri_gen.next()
    p = pent_gen.next()
    h = hex_gen.next()

    while t != p or t != h:
        #print t,p,h
        #sleep(0.5)
        if t < p or t < h:
            t = tri_gen.next()
        if p < t:
            p = pent_gen.next()
        if h < t:
            h = hex_gen.next()
    print t

if __name__ == "__main__":
    sys.exit(main())