#include <fstream>
using namespace std;

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

int x[100005], y[100005], n, m, k, i;

int main(){
	f>>n>>m>>k;
	for (i=1; i<=m; i++) f>>x[i]>>y[i];
	for (i=m; i; i--) if (x[i]<=k) k+=(y[i]-x[i]+1);
	g<<k;
}