Time Limit: 1000ms
Memory Limit: 65536kb
DescriptionAlipay has many independent systems. These systems should be deployed in every Wednesday, but only one system can be deployed at the same time, the others can only wait. Now we need your help to design a plan to reduce the system's average waiting time. Known as follow:
1．All the systems begin to be deployed at the same same, and this time is called STARTING TIME. this is reasonable because engineers start to work at 9:00.
2. Once a system begin to be deployed, it will not stop until finishing.
3. The release time of each system is determined.
4. Each system's waiting time will vary with the planning, the goal is to make the average waiting time smallest.
Now it's your time to solve it.
InputThere are several cases. Every case begins with n(1<=n<=100), the number of system. The next n lines each will start with a name, and following by a number denoting the time the deployment will cost.
The input is ended by n = 0;
OutputFor each case print the average waiting time, the results are rounded to 3 digits after the decimal point.
3 authcenter 10 personal 20 cashier 30 0