package chelper;

import io.InputReader;
import io.OutputWriter;
import misc.SimpleSavingChelperSolution;


public class HS08TEST extends SimpleSavingChelperSolution {

  public void solve(int testNumber, InputReader in, OutputWriter out) {
    wrapSolve(testNumber, in, out);
  }

  @Override
  public void solve(int testNumber) {
    int x = in.nextInt();
    double y = in.nextDouble();

    if (x + 0.5 > y || x % 5 != 0) {
      out.println(y);
    } else {
      out.println(y - x - 0.5);
    }
  }
}