记录编号	385406	评测结果	AAAAAAAAAA
题目名称	[HAOI 2013]花卉节	最终得分	100
用户昵称	kZime	是否通过	通过
代码语言	C++	运行时间	0.170 s
提交时间	2017-03-21 11:12:06	内存使用	15.57 MiB

/*kZime*/
#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <vector>
#include <queue>
#include <stack>
#include <cstdlib>
#include <algorithm>
#define MAXN 1000000
#define ll long long 
using namespace std;
inline ll read() {
	ll k = 0, f = 1; char c = getchar();
	for(; !isdigit(c); c = getchar())if(c == '-') f = -1;
	for(; isdigit(c); c = getchar()) k = k * 10 + c - '0';
	return k * f;
}
/*-----------------------------------------------------------------------------*/

struct f{
	ll p, w;
}fl[MAXN];
ll n, m;

bool cmp(f a, f b) {
	return a.w < b.w;
}

int main() {
#ifndef MYLAB
	freopen("haoi13_t2.in", "r", stdin);
	freopen("haoi13_t2.out", "w", stdout);
#else
	freopen("in.txt", "r", stdin);
#endif

	n = read();
	m = read();
	
	for(ll i = 0; i < n; i++) {
		fl[i].w = read(); 
		fl[i].p = read();
	}

	sort(fl, fl + n, cmp);
	
	ll i = 0, ans = 0;
	while(i < n) {
		ll temp = m / fl[i].w; 
		if(temp > fl[i].p) {
			ans += fl[i].p;
			m -= fl[i].p * fl[i].w;
			i++;
		}
		else {
			ans += temp;
			break;
		}
	}

	printf("%lld", ans);

	return 0;
}