#include<cstdio>

#include<cstring>

#include<iostream>

#include<algorithm>

#include<cmath>

using namespace std;

typedef long long LL;

const LL INF = 1e9+;

const LL maxn = 1e3+;

const LL MOD = 1e9+;

int dp[][maxn][maxn], sum[maxn];

struct node

{

    int X, B;

    bool friend operator < (node A, node B)

    {

        return A.X < B.X;

    }

} P[maxn];

int main()

{

    int n, v, x;

    while(cin >> n >> v >> x)

    {

        for(int i=; i<=n; i++)

            cin >> P[i].X >> P[i].B;

        P[n+].X = x, P[n+].B = ;

        n ++;

        memset(dp, , sizeof(dp));

        memset(sum, , sizeof(sum));

        sort(P+, P++n);

        sum[] = ;

        for(int i=; i<=n; i++)

            sum[i] = sum[i-] + P[i].B;

        int Star;

        for(int i=; i<=n+; i++)

        for(int j=; j<=n+; j++)

        dp[][i][j] = dp[][i][j] = INF;

        for(int i=; i<=n; i++)

        {

            if(P[i].X == x)

            {

                Star = i;

                break;

            }

        }

        dp[][Star][Star] = dp[][Star][Star] = ;

        for(int i=Star; i>=; i--)

        for(int j=Star; j<=n;  j++)

        {

            dp[][i][j] = min(dp[][i][j], dp[][i+][j] + (P[i+].X - P[i].X)*(sum[n]-sum[j]+sum[i]) );

            dp[][i][j] = min(dp[][i][j], dp[][i+][j] + (P[j].X - P[i].X)*(sum[n]-sum[j]+sum[i]) ) ;

            dp[][i][j] = min(dp[][i][j], dp[][i][j-] + (P[j].X - P[i].X)*(sum[n]-sum[j-]+sum[i-]) );

            dp[][i][j] = min(dp[][i][j], dp[][i][j-] + (P[j].X - P[j-].X)*(sum[n] - sum[j-] + sum[i-]) );

        }

        printf("%d\n", min(dp[][][n],dp[][][n])*v);

    }

    return ;

}