1.
Let S=N∪{0}S = \mathbf{N} \cup \{0\}. Define a relation RR from SS to R\mathbf{R} by:
R={(x,y):log⁡ey=xlog⁡e(25),x∈S,y∈R}.R = \left\{(x, y): \log_e y = x \log_e\left(\frac{2}{5}\right), x \in S, y \in \mathbf{R}\right\}.

Then, the sum of all the elements in the range of RR is equal to: