def euler2():
f1, f2, s = 1, 2, 0
while f2 < 4000000:
s += 0 if f2 % 2 else f2
f1, f2 = f2, f1 + f2
return s
print(euler2())
ZGVmIGV1bGVyMigpOgogICAgZjEsIGYyLCBzID0gMSwgMiwgMAogICAgd2hpbGUgZjIgPCA0MDAwMDAwOgogICAgICAgIHMgKz0gMCBpZiBmMiAlIDIgZWxzZSBmMgogICAgICAgIGYxLCBmMiA9IGYyLCBmMSArIGYyCiAgICByZXR1cm4gcwogICAgCnByaW50KGV1bGVyMigpKQ==