Level 29

You see a room which is 10x10m wide (0x0 to 9x9).
Every square has the exact temperature of 18°C. We apply continuously 72°C heat to the field 5x8
What is the temperature (rounded to whole numbers) in the field 1x5 after 121 iterations according to the Gauss-Seidel iteration

Field in the beginning

18181818181818181818
18181818181818181818
18181818181818181818
18181818181818181818
18181818181818181818
18181818181818181818
18181818181818181818
18181818181818181818
18181818181818181818
18181818181818181818

Field after 4 iterations (rounded after 4th iteration)

3456666542
47910101110974
5911131314131295
610131415151514105
610131516171615116
611141518201917126
610131723302621147
59132135554026157
471223511225427146
247142744281694

Temperature in field 1x5 after 121 iterations: