#include <iostream>
using namespace std;
int main()
{
	int t,n,i,score;
	char name[21];
	long sum;
    cin>>t>>n;
	while(t!=0 && n!=0)
    {
		sum=3*n;
		for(i=1;i<=t;i++)
        {
			cin>>name>>score;
			sum-=score;
		}
		cout<<sum<<endl;
		cin>>t>>n;
	}
	system("pause");
	return 0;
}