C++ code: There are n lights, numbered 1~n. The first person turns on all the lights, the second person presses all the switches numbered multiples of 2 (the lights will be turned off), the third person presses all the switches numbered multiples of 3 (the lights that are turned off will Is turned on, the light that is turned on will be turned off), and so on. There are a total of k people, ask which lights are on at the end? Write a program, input n and k, and output the number of the light that is on (k<=n<=1000).

n1n12233knkk<=n<=1000