#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<vector>
using namespace std;
vector<int>vec;
int main()
{
	freopen("charm.in","r",stdin);
    freopen("charm.out","w",stdout);
	int n,m,w[3510],d[3510];
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;i++)scanf("%d%d",&w[i],&d[i]);
	for(int i=1;i<=n;i++)
	if(d[i]>d[i-1]){
		int x,y;
		y=d[i-1];
		d[i-1]=d[i];
		d[i]=y;
		x=w[i-1];
		w[i-1]=w[i],
		w[i]=x;
	}
		int sum=0,ans=0;
		for(int i=1;i<=n;i++)
		while(sum<=m){
		sum=w[i]+sum;
		
		{
		
			ans=ans+d[i];
		}
		
		}
		printf("%d",ans-d[n]-1);

}