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 161°C heat to the field 7x2
What is the temperature (rounded to whole numbers) in the field 1x3 after 74 iterations according to the Gauss-Seidel iteration

Field in the beginning

18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18

Field after 4 iterations (rounded after 4th iteration)

3	4	5	6	6	10	21	32	24	12
4	7	9	10	13	26	57	99	62	28
5	9	11	13	20	43	104	263	108	42
6	10	13	15	21	38	72	114	73	34
6	10	13	16	20	30	45	58	45	23
6	11	14	16	19	24	30	34	28	15
6	10	13	15	17	20	22	23	19	10
5	9	12	14	15	16	17	17	13	7
4	7	9	10	11	12	12	11	8	4
2	4	5	5	6	6	6	5	4	2

Temperature in field 1x3 after 74 iterations:

18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18

3	4	5	6	6	10	21	32	24	12
4	7	9	10	13	26	57	99	62	28
5	9	11	13	20	43	104	263	108	42
6	10	13	15	21	38	72	114	73	34
6	10	13	16	20	30	45	58	45	23
6	11	14	16	19	24	30	34	28	15
6	10	13	15	17	20	22	23	19	10
5	9	12	14	15	16	17	17	13	7
4	7	9	10	11	12	12	11	8	4
2	4	5	5	6	6	6	5	4	2

18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18

3	4	5	6	6	10	21	32	24	12
4	7	9	10	13	26	57	99	62	28
5	9	11	13	20	43	104	263	108	42
6	10	13	15	21	38	72	114	73	34
6	10	13	16	20	30	45	58	45	23
6	11	14	16	19	24	30	34	28	15
6	10	13	15	17	20	22	23	19	10
5	9	12	14	15	16	17	17	13	7
4	7	9	10	11	12	12	11	8	4
2	4	5	5	6	6	6	5	4	2

18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18
18	18	18	18	18	18	18	18	18	18

3	4	5	6	6	10	21	32	24	12
4	7	9	10	13	26	57	99	62	28
5	9	11	13	20	43	104	263	108	42
6	10	13	15	21	38	72	114	73	34
6	10	13	16	20	30	45	58	45	23
6	11	14	16	19	24	30	34	28	15
6	10	13	15	17	20	22	23	19	10
5	9	12	14	15	16	17	17	13	7
4	7	9	10	11	12	12	11	8	4
2	4	5	5	6	6	6	5	4	2