function main(input) {
  	input = input.split(" ");

  	var BasePoint = input[0];
  	var Apoint = input[1];
  	var Bpoint = input[2];
  	console.log(BasePoint,input[1],input[2]);
  
  	AbetweenBase = BasePoint - Apoint;
  
  	BbetweenBase = BasePoint- Bpoint;
  
  	if (Math.abs(AbetweenBase) > Math.abs(BbetweenBase)){
     	console.log("B"); 
    } else {
      	console.log("A");
    } 
  	
}
main(require('fs').readFileSync('/dev/stdin', 'utf8'));