junior = int(input())
senior = int(input())
trace = input()

tax=0

if trace == 'trail':
    tax = junior * 5.50 + senior * 7
elif trace =='cross-country':
    if (junior + senior) >= 50:
     tax = (junior * 8 + senior * 9.50) * 0.75
    else:
        tax = junior * 8 + senior * 9.50
elif trace =='downhill':
    tax = junior *12.25 + senior * 13.75
elif trace =='road':
    tax = junior * 20 + senior*21.50
tax = tax*0.95
tax = round(tax,2)
print(f'{tax:.2f}')