Who has composed more symphonies than any other person? With how many symphonies are they credited?

Leif Segerstam is currently sitting at an incredible 371 symphonies and counting - he's still alive and composing more (age 80 as of the writing of this question). However, many of his works may not qualify as symphonies in the traditional sense as they are single-movement compositions which could more properly be called symphonic poems (similar to those written by Liszt).

For classical composers using the full symphonic form of three or more movements, the answer would be Joseph Haydn, who clocks in at 106 to 108 symphonies: 104 numbered and two extras discovered in the early 20th century were written for full orchestra and are complete. Two further works are sometimes counted as symphonies for him: One symphony that only has one surviving movement and one "sinfonia" piece for two string and two wind instruments which should more properly be considered a sonata.

https://en.wikipedia.org/wiki/Leif_Segerstam
https://en.wikipedia.org/wiki/List_of_symphonies_by_Joseph_Haydn