#include <fstream.h>
ifstream fin("stergeri.in");
ofstream fout("stergeri.out");
long n,m,k,i,x,y,s,a[1][100001],j;
int main() {
fin>>n>>m>>k;
//for (i=1;i<=n;++i)
//	v[i]=i;
for (i=1;i<=m;++i)
	for (j=0;j<=1;++j)
		fin>>a[j][i];
for (i=m;i>=1;--i)
	  if (k>=a[0][i])
		  k+=a[1][i]-a[0][i]+1;
fout<<k;
return 0;
}