import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import static java.lang.System.in;

public class No445 {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        String[] inputs = reader.readLine().split(" ");
        int A = Integer.parseInt(inputs[0]);
        int B = Integer.parseInt(inputs[1]);

        int answer = 50 * A + (int) Math.floor((50 * A) / (0.8 + 0.2 * B));

        System.out.println(answer);
    }
}