Months

let months = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'];

function solve(num) {
    if (1 <= num <= 12) {
        index = num - 1;
        console.log(months[index]);
    } else {
        console.log('Error!');
    }
}

solve(2);
solve(4);
solve(12);
solve(13);
solve(0)