#include<fstream>
using namespace std;
ofstream fout("zombie.out");
long long int d,n,k,v[1000100];
void citire();
void rez();
void afis();
int main()
{
	citire();
	rez();
	return 0;
}
void citire()
{
	ifstream fin("zombie.in");
	fin>>d>>n>>k;
	for(int i=1;i<=n;i++)
		fin>>v[i];
}
void rez()
{int c=0;
	int i;
	for(i=1;i<n;i++)
		if((v[i]-v[n]+v[i])<=1)
			c++;
	fout<<c+k;
}