NaN value

The value NaN means Not-A-Number. This value is obtained when you try to do mathematical operations not with numbers, but with something else. For example, an attempt to multiply a string by a number will give such a value:

alert('abc' * 3); // shows NaN

Any operations with NaN still lead to the NaN result:

alert(NaN + 1); // shows NaN

Make two strings. Multiply them over each other. Print the result of the multiplication on the screen.