Level 29

You see a room which is 10x10m wide (0x0 to 9x9).
Every square has the exact temperature of 40°C. We apply continuously 81°C heat to the field 9x8
What is the temperature (rounded to whole numbers) in the field 7x8 after 84 iterations according to the Gauss-Seidel iteration

Field in the beginning

40404040404040404040
40404040404040404040
40404040404040404040
40404040404040404040
40404040404040404040
40404040404040404040
40404040404040404040
40404040404040404040
40404040404040404040
40404040404040404040

Field after 4 iterations (rounded after 4th iteration)

6912131314131295
916202223242321168
12202528303030272011
13222832343434302312
13233034363636322413
14243034363737332616
13233034363736343123
12212730323334364245
91620232425273454115
581112131415192735

Temperature in field 7x8 after 84 iterations: