C++ :

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<cstring>
#include<cmath>
#include<queue>
#define INF 10000000
#define N 1000010
using namespace std;
double ci[N],pi[N];
double dp[N];
int main()
{
    double l,c,m,s;
    int n;
    while(cin>>l>>c>>m>>pi[0]>>n)
    {
        for(int i=1;i<=n;i++)
        {
            scanf("%lf%lf",&ci[i],&pi[i]);
        }
        ci[0]=0,ci[n+1]=l,pi[n+1]=INF;
        s=c*m;
        for(int i=0;i<=n+1;i++)
            dp[i]=INF;
        dp[0]=0;
        int flag=0;
        for(int i=0;i<=n;i++)
        {
            for(int j=i+1;j<=n+1;j++)
            {
                if(s>=ci[j]-ci[i])
                {
                    dp[j]=min(dp[j],dp[i]+pi[i]*(ci[j]-ci[i])/m);
                }
                else
                {
                    if(s>=ci[j]-ci[j-1])
                        dp[j]=min(dp[j],dp[i]+(pi[i]*s+pi[j-1]*(ci[j]-ci[i]-s))/m);
                    else
                    {
                        flag=1;
                        break;
                    }
                }
            }
            if(flag==1)
                break;
        }
        if(dp[n+1]==INF)
            cout<<"No Solution"<<endl;
        else
            printf("%.2lf\n",dp[n+1]);
    }
    return 0;
}