#include <stdio.h>
#define input "stergeri.in"
#define output "stergeri.out"
#define nmax 100001
long n,m,k,x[nmax],y[nmax],i;
int main()
{
 freopen(input,"r",stdin);
 freopen(output,"w",stdout);
 scanf("%ld %ld %ld",&n,&m,&k);
 for (i=1;i<=m;i++)
      scanf("%ld %ld",&x[i],&y[i]);
 for (i=m;i;i--)
     if (x[i]<=k) k+=y[i]-x[i]+1;
 printf("%ld",k);
 return 0;
}