There are $61$ codons in mRNA coding for particular amino acids. $($Some amino acids are coded by more than one codon. That redundancy in codons is referred to as degeneracy$)$

For each codon there needs to be a corresponding tRNA that will bring the respective amino acid to the ribosome and pairs with the mRNA codon during elongation.$$

However, there are only about $45$ tRNAs in eukaryotic cells that can recognize $61$ codons. How is that possible? Explain in a few sentences.