How to find a element which is between a pair in the set of pair

set<pair<int,int> >s;
pair<int,int>a0=make_pair(1,10);// pair  is kind of range of integer
air<int,int>a1=make_pair(11,50);
s.insert(a0);
s.insert(a1);

Now I need a function which return true when i search any integer which lies between range of any pair int the set.