Rewrite the Following Nested If-Else Statement as an Equivalent Switch

Rewrite the following nested if-else statement as an equivalent switch statement.
if (letter == 'A' | | letter == 'a') System.out.println("Excellent");
else if (letter == 'B' | | letter == 'b') System.out.println("You can do better");
else if (letter == 'C' | | letter == 'c') System.out.println("Try harder");
else if (letter == 'D' | | letter == 'd') System.out.println("Try much harder");
else System.out.println("Try another major! ");