A tilting level was used to run precise levels to a construction project benchmark from benchmark DAM, which had an elevation of 345.901 m. The line was run along a road that goes up a steep incline. To expedite the job, back sight distances were kept to 50 m while foresight distances were 25 m. The total length of differential levels was 5248 m. The measured elevation difference was 21.051 m. 

What is the corrected project benchmark’s elevation if the instrument has a sight line that declines at the rate of 0.5 mm per 50 m?