#include<fstream>
using namespace std;
ifstream f("stergeri.in");
ofstream g("stergeri.out");
int n, m, k, i, a[100001], b[100001];
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=k+b[i]-a[i]+1;
	g<<k;
	return 0;
}