Cal key fig based on Dates(key fig)

Hi,

I have got one Keyfigure in date formet as DD/MM/YYYY.(KEYFIG 1)

Based on this i have to define a second key fig (KEYFIG2) as below.

If KEYFIG1 is DD/MM/YYYY then the KEYFIG2 should come as YYYYSHIP.

It would be great if any of you can provide solution for this. Pls...