LTA claim in 2018

Under Rule 2B, exemption will be available in respect of 2 journeys performed in a block of 4 calendar years commencing from the calendar year 1986. Where such travel concession or assistance is not availed by the individual during any block of 4 calendar years, one such unavailed LTC will be carried forward to the immediately succeeding block of 4 calendar years and will be eligible for exemption. 
Example: 
An employee does not avail any LTC for the block 2014-17. He avails it during 2018. He is allowed to carry forward maximum one such holiday to be used in the succeeding block. Therefore, he will be eligible for exemption and two more journeys can be further availed.
so, I can claim thrice in the block 2018-2012.
so my doubt is while claiming my first LTC now, I have to give tickets to the employer for year 2018 or pertaing to block 2014-17?