#include<fstream>
using namespace std;

int lungime,n,k,dp[1000010],v[1000010];

void citirensolve() {

    ifstream in("zombie.in");
    int i,j;
    in>>lungime>>n>>k;
    j=1;
    for(i=1;i<=n;i++) {
        in>>v[i];
        while(v[i]-v[j]>lungime)
            j++;
        if(dp[i-1]+1<dp[j-1]+k)
            dp[i]=dp[i-1]+1;
        else
            dp[i]=dp[j-1]+k;
    }
    in.close();

}

void afisare() {

    ofstream out("zombie.out");
    out<<dp[n]<<'\n';
    out.close();

}

int main () {

    citirensolve();
    afisare();
    return 0;

}