题解 | #网购#

n=list(map(float,input().split()))
if n[1]==11 and n[3]==1 and n[0]*0.7>50:
    print(f"{(n[0]*0.7-50):.2f}")
elif n[1]==11 and n[3]==1 and n[0]*0.7<=50:
    print("0.00")
elif n[1]==11 and n[3]==0:
    print(f"{(n[0]*0.7):.2f}")
elif n[1]==12 and n[3]==1 and n[0]*0.8>50:
    print(f"{(n[0]*0.8-50):.2f}")
elif n[1]==12 and n[3]==1 and n[0]*0.8<=50:
    print("0.00")
else:
    print(f"{(n[0]*0.8):.2f}")