package main

import (
  "bufio"
  "fmt"
  _ "math"
  _ "math/big"
  "os"
  "strconv"
  "strings"
)

func main() {                                                                                           scanner := bufio.NewScanner(os.Stdin)
  th := 0
  var a, b float64
  for scanner.Scan() {
    th += 1
    text := scanner.Text()
    x2 := strings.Split(text, " ")
    a, _ = strconv.ParseFloat(x2[0], 64)
    b, _ = strconv.ParseFloat(x2[1], 64)
    if th == 1 {
      break
    }                                                                                                   }
  fmt.Println(int64(50.0*a + (50.0 * a / (0.8 + 0.2*b))))
}