import java.util.Arrays; import java.util.LinkedList; import java.util.Scanner; import java.util.TreeSet; public class Main { public static long MOD = 1000000007; public static void main(String[] args) { Scanner sc = new Scanner(System.in); final long N = sc.nextLong(); final long K = sc.nextLong(); final long upper = 500 * N; final long lower = 8 + 2 * K; System.out.println(50 * N + (upper / lower)); } }