#include <iostream>
#include<fstream>
using namespace std;

int main()
{
    ifstream fin("energii.in");
	int g, w, eg[10001], cg[10001],cmin,prodmax,mem;
	fin >> g >> w;
	for (int i = 1; i <= g; i++)
	{
		fin >> eg[i] >> cg[i];
	}
	prodmax = eg[1];
	for (int i = 2; i <= g; i++)
	{
		if (prodmax < eg[i])
		{
			prodmax = eg[i]; mem = i;
		}

	}
	int mincreat = cg[mem];
	for (int i = 1; i <= g; i++) {
		int creat = 0;
		int ener=0;
		if (mem != i) {
			while (prodmax > ener)
			{
				ener = eg[i] + ener;
				creat = creat + cg[i];
			}
			if(creat<mincreat)
			{
				mincreat = creat;
			}

		}
	}
	ofstream fout("energii.out");
	fout << mincreat;

	fin.close();
	fout.close();
	return 0;
}