Theorem jad

Deduction form of ja. (Contributed by Scott Fenton, 13-Dec-2010.) (Proof shortened by Andrew Salmon, 17-Sep-2011.)

Hypotheses
jad.1
\( \vdash \varphi \rightarrow \neg \psi \rightarrow \theta \)
jad.2
\( \vdash \varphi \rightarrow \chi \rightarrow \theta \)
Conclusion
\( \vdash \varphi \rightarrow (\psi \rightarrow \chi) \rightarrow \theta \)
Proof
jad.1
l1
com12 _
jad.2
com12 _
ja l1 _
com12 _