| 1 | 0 (a1 n) |
| 2 | (a1 n) < n |
| 3 | 0 (a2 n) |
| 4 | (a2 n) < n |
| 5 | 12. (a1 n) = (a2 n) n 0 (a1 rem n) |
| 6 | 12. (a1 n) = (a2 n) n (a1 rem n) < n |
| 7 | 12. (a1 n) = (a2 n) n 0 (a2 rem n) |
| 8 | 12. (a1 n) = (a2 n) n (a2 rem n) < n |
| 9 | 12. (a1 n) = (a2 n) n 13. (a1 rem n) = (a2 rem n) n a1 = a2 |