Firework Show

Students bought discounted fireworks after New Year's Day and are setting them off.

During the firework show, N students set off fireworks. Each student uses a fixed period; periods may be the same or different. We observe time in whole seconds, and fireworks also go off at whole seconds.

Determine how many distinct seconds show at least one firework in the sky before the show ends.

The first line contains the number of students N (1 ≤ N ≤ 100) and the ending time C (1 ≤ C ≤ 2,000,000). Each of the next N lines contains one student's firework period. Each period is a natural number between 1 and C, inclusive.

Print the number of distinct seconds between second 1 and second C, inclusive, when at least one firework is visible in the sky.

                                    2                                    1     2     1           1           1     2     10  1  2  3  4  5  6  7  8  9 10 11 12 13 14 15 16 17 18 19 20            1     2     3           4           5     6     7

In the diagram above, fireworks go off at seconds 4, 6, 8, 12, 16, 18, and 20, where the numbers 1 and 2 are written. At second 12, two fireworks go off at the same time, but that second is counted only once.