Opener's Rebid after Partner's Negative Double 6

Opener's Rebid after Partner's Negative Double 6

Question:

You are South. Matchpoints. None vul. 

You hold: 

QJ87
AJ3
KJ87
J10

What is your next call on this auction:

  West    North    East    South  
   1diamonds icon
1hearts iconDbl 2hearts icon?

Answer: