import math
import sys
from operator import itemgetter
input = sys.stdin.readline

# a = int(input().rstrip())
# a, b = map(int, input().rstrip().split())
# D = list(map(int, input().rstrip().split()))
# H = [int(input().rstrip()) for _ in range(L)]
# DD = [[0 for j in range(100)] for i in range(200)]

# if __name__ == '__main__':

P, Q = map(float, input().rstrip().split())
print(P*Q*100/(P*Q+(100-P)*(100-Q)))