from decimal import Decimal, getcontext

getcontext().prec = 50  # Setting a high precision to handle large numbers accurately

n, g, v = map(int, input().split())
coins = n // 5
total_gas = coins * g

# Using Decimal for high precision division
result = Decimal(str(total_gas)) / Decimal(str(v))
result = result.normalize()

# Convert result to string for formatting
result_str = format(result, 'f')

# Process the string to remove trailing zeros and unnecessary decimal points
if '.' in result_str:
    integer_part, fractional_part = result_str.split('.')
    fractional_part = fractional_part.rstrip('0')
    if fractional_part:
        print(f"{integer_part}.{fractional_part}")
    else:
        print(integer_part)
else:
    print(result_str)