How do you calculate the degrees of freedom in a two-way Anova?

Anova: Two-Factor With Replication SUMMARY Japanese Chinese Total System 1 Count 25 25 50 Sum 245 303 548 Average 9.8 12.12 10.96 Variance 5.25 4.11 5.957551 System 2 Count 25 25 50 Sum 215 214 429 Average 8.6 8.56 8.58 Variance 2.5 4.506667 3.432245 Total Count 50 50 Sum 460 517 ANOVA Source of Variation SS df MS F P-value F crit Sample 141.61 1 141.61 34.60937 0.0000000587 3.940163 Columns 32.49 1 32.49 7.94053 0.00586988 3.940163 Interaction 34.81 1 34.81 8.507536 0.004403603 3.940163 Within 392.8 96 4.091667 Total 601.71 99