Integral of a specific region on the x and y-axis in histogram

Pls in getting a count under a particular peak I usually use something like this
and it gives me the integral in that region of the x-axis.
But my peak does not start from zero on the y-axis want to know if there is a way to get an integral starting for instance from 100 on the y-axis and 20-50 on the x-axis.


How should I write it pls

The documentation provided is pretty clear:

An example:

   TH2D *h = new TH2D("h","",200,0,250,200,-150,150);                                                                                                   
   for (int i=0;i<5000;i++) {                                                      
      double x = gRandom->Uniform(0,250);                                          
      double y = gRandom->Uniform(-150,150);                                       
   //Integrate from bin (10,10) to bin (30,30)                                     
   std::cout << h->Integral(10, 30, 10, 30) << "\n";                               
   //Integrate roughly from the point (10,10) to the point (30,30)                 
   int firstxbin = h->GetXaxis()->FindBin(10);                                     
   int lastxbin = h->GetXaxis()->FindBin(30);                                      
   int firstybin = h->GetYaxis()->FindBin(10);                                     
   int lastybin = h->GetYaxis()->FindBin(30);                                      
   std::cout << h->Integral(firstxbin, lastxbin, firstybin, lastybin) << "\n";     

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