#include <fstream>
using namespace std;

#define nmax 2000001
long n,m,k;
long x[nmax],y[nmax];

inline void citire()
{
	ifstream in("stergeri.in");
	in>>n>>m>>k;
	for(long i=1;i<=m;i++)
		in>>x[i]>>y[i];
}

ofstream out("stergeri.out");
void rez()
{
	long i;
	for(i=1;i<=m;i++)
		if(x[i]<=k)
			k += y[i]-x[i]+1;
	out<<k;

}

int main()
{	
	citire();
	rez();
	return 0;
}