Estimate (on paper) the output of this function

Question

I am given a function:

define f(i,j):
    if i equals to 0 and j equals to 0:
        return 1
    else if i equals to 0 and j not equals to 0:
        return f(j-1,j-1)
    else:
        return f(i-1,j)+f(i-1,j-1)

and I am told to estimate f(14,14) quickly. I tried expanding everything out but did not see any pattern. The hint I was given was to imagine a grid with values at every lattice point, with (0,0) and (0,1) being 1. I don’t see how exactly this helps with the estimation, could someone guide me on this please? Thank you!