#include <iostream>
using namespace std;

int main()
{
		int arr[100];
		int sum=0;
		int bar[100]={0};
		int n;
	while(cin>>n&&n!=-1)
	{	for (int i=0;i<=n-1;++i)
			cin>>arr[i]>>bar[i+1];
		for (int ii=0;ii<=n-1;++ii)
			sum+=arr[ii]*(bar[ii+1]-bar[ii]);
		cout<<sum<<" "<<"miles"<<endl;
		sum=0;
	}
	return 0;
}