#include<fstream>
using namespace std;
ifstream in("stergeri.in");
ofstream out("stergeri.out");
int m;
long long n,k,a,b,sol,dc;
int main()
{	int i;
	in>>n>>m>>k;
	sol=k;
	for(i=1;i<=m;i++)
	{	in>>a>>b;
		if(k<a)
			dc=dc+b-a+1;
		else if(a<=k && k<=b)
			sol=sol+b-a+1+dc;
		else if(b<k)
			sol=sol+b-a+1;	
	}
	in.close();
	out<<sol;
	out.close();	
	return 0;
}