#include <fstream>
#include <algorithm>
using namespace std;

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

struct doua {int s, d;};

doua v[100005];
int i, j, n, m, k;

inline bool comp (doua fx, doua fy) { return fx.s<fy.s; }

int main(){
	f>>n>>m>>k;
	for (i=1; i<=m; i++) f>>v[i].s>>v[i].d;
	
	sort (v+1, v+m+1, comp);
	
	for (i=1; i<=m && k>=v[i].s; i++) 
		k+=(v[i].d-v[i].s+1);
	
	g<<k;
}