#include <fstream>
#define N 100001
using namespace std;

typedef struct {long st,dr;} INTERVAL;
INTERVAL A[N];
long n,i,rez;
int m,k;

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

int main()
{
	f>>n>>m>>k;
	for (i=1;i<=m;++i)
		f>>A[i].st>>A[i].dr;
	rez=k;
	for (i=m;i>=1;--i)
		if (A[i].st<=rez)
			rez+=A[i].dr-A[i].st+1;
	g<<rez;
	f.close();
	g.close();
	return 0;
}