1 //#pragma comment(linker, "/STACK:167772160")//手动扩栈~~~~hdu 用c++交
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <cstdlib>
 5 #include <iostream>
 6 #include <queue>
 7 #include <stack>
 8 #include <cmath>
 9 #include <set>
10 #include <algorithm>
11 #include <vector>
12 #include <map>
13 // #include<malloc.h>
14 using namespace std;
15 #define clc(a,b) memset(a,b,sizeof(a))
16 #define LL long long
17 const int inf = 0x3f3f3f3f;
18 const double eps = 1e-5;
19 // const double pi = acos(-1);
20 const LL MOD = 9901;
21 const int N = 1010;
22
23 // inline int r(){
24 //     int x=0,f=1;char ch=getchar();
25 //     while(ch>'9'||ch<'0'){if(ch=='-') f=-1;ch=getchar();}
26 //     while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
27 //     return x*f;
28 // }
29 struct node{
30     int x,y;
31 }p[N];
32
33
34 bool cmp(node a,node b){
35     return a.x<b.x;
36 }
37
38 int dp[N][N][2];
39 int sum[N];
40
41 int main(){
42     int n,v,x;
43     while(~scanf("%d%d%d",&n,&v,&x)){
44         for(int i=1;i<=n;i++){
45             scanf("%d%d",&p[i].x,&p[i].y);
46         }
47         p[++n].x=x;
48         p[n].y=0;
49         sort(p+1,p+1+n,cmp);
50
51         sum[0]=0;
52         for(int i=1;i<=n;i++){
53             sum[i]=sum[i-1]+p[i].y;
54         }
55         int tem;
56         for(int i=1;i<=n;i++){
57             if(p[i].x==x){
58                 tem=i;
59                 break;
60             }
61         }
62
63         for(int i=0;i<=n;i++){
64             for(int j=0;j<=n;j++){
65                 dp[i][j][0]=dp[i][j][1]=inf;
66             }
67         }
68         dp[tem][tem][1]=dp[tem][tem][0]=0;
69
70         for(int i=tem;i>=1;i--){
71             for(int j=tem;j<=n;j++){
72                 if(i==j) continue;
73
74                 dp[i][j][0]=min(dp[i][j][0],dp[i+1][j][0]+(sum[i]+sum[n]-sum[j])*(p[i+1].x-p[i].x));
75                 dp[i][j][0]=min(dp[i][j][0],dp[i+1][j][1]+(sum[i]+sum[n]-sum[j])*(p[j].x-p[i].x));
76
77                 dp[i][j][1]=min(dp[i][j][1],dp[i][j-1][0]+(sum[i-1]+sum[n]-sum[j-1])*(p[j].x-p[i].x));
78                 dp[i][j][1]=min(dp[i][j][1],dp[i][j-1][1]+(sum[i-1]+sum[n]-sum[j-1])*(p[j].x-p[j-1].x));
79             }
80         }
81         printf("%d\n",v*min(dp[1][n][0],dp[1][n][1]));
82     }
83     return 0;
84 }