the 2050 volunteer organize Run Chase rise Sun activity start Apr 25 730 runner complete 6 km trail Yunqi townthere n1 checkpoint trail they number 0 1 n a runner start checkpoint 0 finish checkpoint n no checkpoint skippable run checkpoint 0 checkpoint 1 checkpoint 1 checkpoint 2 Look picture note section clarificationbetween adjacent checkpoint m different path choose for 1le ile n run checkpoint i1 checkpoint runner choose exactly m possible path the length jth path checkpoint i1 b_ij 1le jle m 1le ile nto test trail m runner each runner run checkpoint 0 checkpoint n visit checkpoint every path pair adjacent checkpoint need run exactly runner if runner choose path length l_i checkpoint i1 1le ile n tiredness min_i1n l_i ie minimum length path takesplease arrange path m runner minimize sum tiredness