//OPCIÓN 1
function getGrade (s1, s2, s3) {
avg = (s1+s2+s3)/3;
if (avg < 60) return "F";
else if (avg < 70) return "D";
else if (avg < 80) return "C";
else if (avg < 90) return "B";
else return "A";
}
//OPCIÓN 2
function getGrade(...scores) {
let avg = scores.reduce((a, b) => a + b, 0) / scores.length;
if (avg < 60) return "F";
else if (avg < 70) return "D";
else if (avg < 80) return "C";
else if (avg < 90) return "B";
else return "A";
