[หลาน]

2017 soldiers were lined up in a single file. The commander ordered them to number off 1, 2, 3 4, 5, 1, 2, 3, 4, 5, 1 ... starting from the first soldier. He then ordered them to number off 1, 2, 3, 4, 1, 2, 3, 4, 1 ... starting from the last soldier. How many soldiers had the same number both times? (ตอบ 108) ช่วยอธิบายด้วยคะ หลานถามมา แต่ทำไม่ได้คะ ขอบคุณคะ