Level 29

You see a room which is 10x10m wide (0x0 to 9x9).
Every square has the exact temperature of 21°C. We apply continuously 112°C heat to the field 8x7
What is the temperature (rounded to whole numbers) in the field 2x9 after 78 iterations according to the Gauss-Seidel iteration

Field in the beginning

21212121212121212121
21212121212121212121
21212121212121212121
21212121212121212121
21212121212121212121
21212121212121212121
21212121212121212121
21212121212121212121
21212121212121212121
21212121212121212121

Field after 4 iterations (rounded after 4th iteration)

3567777652
5810121212121184
610131516161614116
712151718181816127
7121618191919191710
7121618192022283320
7121618192130507439
61114161722377818365
581112131728497439
24667915232817

Temperature in field 2x9 after 78 iterations: