#include <iostream>#include <cstdio>#include <cstring>#include <algorithm>using namespace std;int dp[1005][1005][2];const int inf = 1000000000;struct Node{int x;int v;};Node node[1005];int sum[1005];bool cmp(const Node &n1,const Node &n2){return n1.x<n2.x;}int getDelay(int i,int j){if(i>j)return 0;return sum[j]-sum[i-1];}int DP(int n,int x){int res;for(int i = 1;i<=n;i++)if(node[i].x==x){res = i;break;}for(int i = 1;i<=n;i++)for(int j = 1;j<=n;j++)dp[i][j][0] = dp[i][j][1] = inf;dp[res][res][0] = dp[res][res][1] = 0;for(int i = res;i>=1;i--)for(int j = res;j<=n;j++){if(i==j)continue;int delay = getDelay(1,i-1)+getDelay(j+1,n);dp[i][j][0] = min(dp[i][j][0],dp[i+1][j][1]+(delay+node[i].v)*(node[j].x-node[i].x));dp[i][j][0] = min(dp[i][j][0],dp[i+1][j][0]+(delay+node[i].v)*(node[i+1].x-node[i].x));dp[i][j][1] = min(dp[i][j][1],dp[i][j-1][0]+(delay+node[j].v)*(node[j].x-node[i].x));dp[i][j][1] = min(dp[i][j][1],dp[i][j-1][1]+(delay+node[j].v)*(node[j].x-node[j-1].x));}return min(dp[1][n][1],dp[1][n][0]);}int main(){int n,x,v;while(scanf("%d %d %d",&n,&v,&x)!=EOF){for(int i = 1;i<=n;i++){scanf("%d %d",&node[i].x,&node[i].v);}node[++n].x = x;node[n].v = 0;sort(node+1,node+n+1,cmp);for(int i = 1;i<=n;i++){sum[i] = sum[i-1]+node[i].v;}int ans = DP(n,x);printf("%dn",ans*v);}}
