OA question- Today 19-11-2023

Question

Two killers, Dahmer and Dexter are standing on the circumference a circular forest.They are trying to kill each other but can only make moves turn by There are trees between them on the left and right arcs of the circle .in each turn, a person can either cut one of his adjacent trees or ifthe other person is standing right next to him, kill that person Lets say represents the initial number of trees in the clockwise arcand represents the initial number of trees in the counter-clockwisearc, from Dahmer to Dexter (x, y)is a suitable configuration for Dahmer, if he will be able to killDexter and come out alive, given Dahmer moves first. You are given two numbers A and B You need to find the count of all configurations (x, y) such thatr<= A.y<= B and ( . ) is a suitable configuration for DahmerSince the answer can be large, you need to print the answer modulo10 ^ 9 + 7