# include <fstream>
using namespace std;
ifstream f ("stergeri.in");
ofstream g ("stergeri.out");
int a[100005],b[100005],i,n,m,k,aux;



int main ()
{
	f>>n>>m>>k;
	for (i=1;i<=m;i++)
		f>>a[i]>>b[i];
	
	
	for (i=m;i>=1;i--)
	if (a[i]<=k)
		k+=b[i]-a[i]+1;
	g<<k;
	return 0;
}