Henry Ernest Dudeney/Puzzles and Curious Problems/145 - The Printer's Problem

by : $145$

 * The Printer's Problem
 * A printer had an order for $10 \, 000$ bill forms per month,
 * but each month the name of the particular month had to be altered:
 * that is, he printed $10 \, 000$ "JANUARY", $10 \, 000$ "FEBRUARY", $10 \, 000$ "MARCH", etc.;
 * but as the particular types with which these words were to be printed had to be specially obtained, and were expensive,
 * he only purchased just enough movable types to enable him, by interchanging them,
 * to print in turn the whole of the months of the year.
 * How many separate types did he purchase?
 * Of course, the words were printed throughout in capital letters, as shown.