I was reading about the ethereum address generation process. I am very confused that when Private key generated is processed under "Elliptic Curve Digital Signature Algorithm" , we get a public key which is a point on graph. We take x & y co-ordinate of that point. Below is a sample of such process
I am not able to understand is how can we have alphabets in the co-ordinates. I think it should have only numbers. I know that public key is denoted in hexadecimal format but how come co-ordinates have alphabets in it . Can anyone please explain it to me.