#include <fstream>

using namespace std;

ifstream f ("zombie.in");
ofstream g ("zombie.out");

int nr, n, cost;
int v[1000005];
long long rez;

void Read ()
{
   f >> nr >> n >> cost;

   for (int i=1; i<=n; i++)
       f >> v[i];
}

void Solve ()
{
    for (int i=1; i<=n-1; i++)
    {
        if (v[i+1] - v[i] > nr)
        {
            rez ++;
            continue;
        }

        int j = i + 1;

        while (v[j] - v[i] <= nr && j - i + 1 <= nr && j <= n)
            j ++;

        rez += min(cost, j - i + 1);

        i = j;
    }
    g << rez;
}

int main()
{
   Read();
   Solve();
    return 0;
}