2778:Ride to School-poj

#include<iostream>
#include<stdio.h>
#include<string.h>
#include <stdlib.h>
#include<vector>
#include<queue>
#include<math.h>
using namespace std;
int main()
{
    int n;
    int v,t;
    while((cin>>n)&&(n!=0))
    {
        double time;
        double min = 0x7fffffff;
        for(int i=1;i<=n;i++)
        {
            cin>>v>>t;
            if(t < 0)
                continue;
            time=t+(4.5/double(v))*3600;//计算每个同学的时间
            if(time<min)//取时间最短的那个
            {
                min=time;
            }
        }
        cout<<ceil(min)<<endl;//ceil向上取
    }
    
    return 0;
}