Data File Format: The data file for this program is a sequential file with a 9 columns-format of the sequential number, longitude, latitude, magnitude, time from the mainshock in days, depth, year, month, and day. The first row of the data is the title. The second row corresponds to the main shock (not used in this program, but is used in other programs such as [etas.f]). The time (usually in days) is measured from the main shock (t = 0). If aftershock in an early stage of the sequence (e.g., from t = 0 to 0.01 day) are not included because of incomplete observation, it is better to set the starting time of fitting at the beginning of the aftershock data (e.g., 0.01). 0 < Tstart < t_1 < . . . < t_i < t_{i+1} < . . . < t_n < Tend in 5th column. Magnitudes in 4th column are used only in selecting the aftershocks by giving a threshold magnitude.