# include <fstream>
using namespace std;
ifstream fin("stergeri.in");
ofstream fout("stergeri.out");
int a[1005],b[1005],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/2;i>=1;i--)
	if (a[i]<=k)
		k=k+b[i]-a[i]+1;
	fout<<k;
	fin.close();
	fout.close(); 
	return 0;
}