1. P ⊃ ~M
2. C ⊃ M
3. ~L v C
4. (~P ⊃ ~E) • (~E ⊃ ~C)
5. P v ~P / ∴ ~L
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6. ~M ⊃ ~C 2 Transposition
7. P ⊃ ~C 1,6 Hypothetical Syllogism
8. ~P ⊃ ~E 4 Simplification
9. E ⊃ P 8 Transposition
10. (~E ⊃ ~C)• (~P ⊃ ~E) 4 Commutation
11. ~E ⊃ ~C 10 Simplification
12. C ⊃ E 11 Transposition
13. C ⊃ P 9,12 Hypothetical Syllogism
14. C ⊃ ~C 7,13 Hypothetical Syllogism
15. ~C v ~C 14 Material Implication
16. ~C 15 Tautology
17. ~L 3,8 Disjunctive Syllogism
QED