How can I integrate 2D Histogram

I have a 2D histogram h1 which is a measure of length (from 0 to 10 cm) at y axis verses momentum (0 to 60 GeV/)at x axis. I want to know the number of entries above 5cm and 30GeV/c. I tried to use Double_t Integral(Int_t binx1, Int_t binx2, Int_t biny1, Int_t biny2, Option_t* option = β€œβ€) const
but it needs bin number at x1,x2,y1,y2 . I don’t know the bin number at 5cm or 30 GeV/c. :confused:

Is there any method to do the integral using cm or GeV/c range ratherthan bin range?

Your help is appreciated

Int_t TH1::FindBin (Double_t x, Double_t y = 0, Double_t z = 0)