> //这是第一份代码，wa！！！
> #include <iostream>
> #include <cmath>
> using namespace std;
> int main()
> {
> 	int n;
> 	double a,b,t,min;
> 	while(1)
> 	{
> 		cin>>n;
> 		if(n == 0)
> 			break;
> 		min=0.0;
> 		for(int i = 0; i != n; i++)
> 		{
> 			cin>>a>>b;
> 			if(b < 0) continue;
> 			t = ceil(4.5*(double)3600/a + b);
> 			if(i == 0) min = t;
> 			else if(min > t) min = t;
> 		}
> 		cout<<(int)min<<endl;
> 	}
> 	return 0;
> }
> 
> //这是第二份，ac！！！！
> #include <iostream>
> #include <cmath>
> using namespace std;
> int main()
> {
> 	int n,a,b;
> 	double t,min;
> 	while(1)
> 	{
> 		cin>>n;
> 		if(n == 0)
> 			break;
> 		min=1e18;
> 		for(int i = 0; i < n; i++)
> 		{
> 			cin>>a>>b;
> 			if(b >= 0)
> 			{
> 				t = ceil(4.5*(double)3600/(double)a + (double)b);
> 			    if(t < min) 
> 					min = t;
> 			}
> 		}
> 		cout<<(int)min<<endl;
> 	}
> 	return 0;
> }