Umut, the nominal lenght is 25 foot or 7,62 m. The actual length is about 33 foot or 10 m. The additional length is provided as light protection so you can load the film on so-called daylight spools which should be done in subdued light or at least in the shadow.
Since one foot of Regular-Eight film contains 80 frames, you have 2000 frames per roll side, a total of 4000 after processing. Naturally, the two sides need to be spliced together. Those in charge of processing have the right to cut off the waste length but you have the right for 4000 frames. It is good practice to run the film forward in the closed camera to counter Zero, expose no more than 25 ft., and then let the film run out in the again closed camera (cap on lens, variable shutter closed, etc.).
The processor should add leader film to the picture sections, preferably of white colour.