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