#include<fstream>
using namespace std;
ifstream f("stregeri.in");
ofstream g("stregeri.out");
int n,m,k,i,x[100001],y[100001];
int main()
{
	f>>n>>m>>k;
	for(i=1;i<=n;i++) f>>x[i]>>y[i];
	for(i=m;i>=1;i--) if(x[i]<=k) k=k+y[i]-x[i]+1;
	g<<k;
	g.close();
	return 0;
}