#include <fstream>

using namespace std;

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

int d,k,t,i,j;
int st,dr,mij,rez;
int mag[100001];

int main()
{
    f>>d>>k>>t;
    for (i=1;i<=k;i++)
        f>>mag[i];
    st=1,dr=d;
    while (st<=dr)
    {
        mij=(st+dr)/2;
        int paini=mij, nemancat=t;
        for (i=1;i<=k;i++)
        {
            int dist=mag[i]-mag[i-1];
            if (paini>=dist)
                paini-=dist;
            else
            {
                nemancat-=(dist-paini);
                paini=0;
            }
            paini=mij;
            if (nemancat<0)
                break;
        }
        if (nemancat>=0)
        {
            int dist=d-mag[k];
            if (paini>=dist)
                    paini-=dist;
                else
                {
                    nemancat-=(dist-paini);
                    paini=0;
                }
                paini=mij;
        }

        if (nemancat>=0)
        {
            rez=mij;
            dr=mij-1;
        }
        else
            st=mij+1;
    }
    g<<rez;
    return 0;
}