KöMaL 2016 C1337

Csongor's wife sewed a leather sheath decorated with 77 beads for his husband's mouth harp, and gave it to him as a birthday present. Csongor liked it so much that he decided to surprise every member of his heritage preservation mouth harp band with a sheath like his own. He presented the sheaths in the main yurt erected for the celebration of the winter solstice. The yurt had a maximum capacity of 50 persons. Since the beads were bought in packets of 100, 7 beads remained, so Csongor's wife decorated her traditional headdress with them. How many members are there in Csongor's mouth harp band?