1 #include<cstdio>
 2 #include<algorithm>
 3 
 4 using namespace std;
 5 
 6 struct moy{
 7     int x,y;
 8     bool operator < (const moy a) const
 9     {
10         return x < a.x;
11     }
12 }t[25];
13 int h[25];    //已经使用的硬币数 
14 int n,c,p,ans;
15 
16 int main()
17 {
18     scanf("%d%d",&n,&c);
19     for (int i=1; i<=n; ++i)
20         scanf("%d%d",&t[i].x,&t[i].y);
21     
22     sort(t+1,t+n+1);
23     p = n+1;
24     while (t[--p].x>=c) ans += t[p].y;    
25     while (1)
26     {
27         int s = c;    //s剩余的钱 
28         for (int i=p; i>=1; --i)
29         {
30             int cnt = min(t[i].y, s/t[i].x);
31             s -= t[i].x*cnt;    //cnt使用硬币的数量 
32             h[i] = cnt;
33         }
34         if (s>0)
35             for (int i=1; i<=p && s>0; ++i)
36                 if (t[i].y>h[i]) s -= t[i].x, h[i]++;
37         if (s<=0)
38         {
39             int cnt = 1e9;
40             for (int i=1; i<=p; ++i)
41                 if (h[i]) cnt = min(cnt,t[i].y/h[i]);    //cnt有多少可以这样，搭配的组合 
42             ans += cnt;
43             for (int i=1; i<=p; ++i)
44                 if (h[i]) t[i].y -= cnt*h[i];
45         }
46         else break;  
47     }
48     printf("%d",ans);
49     return 0;
50 }