#include<iostream>
#include <algorithm>
const int N = 260;
struct cow{
	int w,t;
	double v;
}cows[N];
int W,n,sumW,sumT;
bool cmp(cow x,cow y){
	return x.v < y.v;
}
int main(){
	scanf("%d%d",&n,&W);
	for(int i = 1;i <= n;i ++){
		scanf("%d%d",&cows[i].w,&cows[i].t);
		cows[i].v = cows[i].w * 1.0 / cows[i].t;
	}
	std::sort(cows + 1,cows + n + 1,cmp);
	for(int i = 1;i <= n;i ++){
		sumW += cows[i].w;
		sumT += cows[i].t;
		if(sumW >= W) break;
	}
	printf("%d",sumT * 1000 / sumW);
	return 0;
}

30？