import java.util.concurrent.Callable;

class FindMaxCallable implements Callable<Double> {
    final double[] arr;
    int from;
    int to;

    public FindMaxCallable(double[] arr, int from, int to){
        this.arr = arr;
        this.from = from;
        this.to = to;
    }

    @Override
    public Double call(){
        double localMax = Double.MIN_VALUE;
        for(int i=from; i<to; i++){
            if(arr[i] > localMax){
                localMax = arr[i];
            }
        }
        return localMax;
    }
}