#include <stdio.h>
#include <ctype.h>
#define L 100003
using namespace std;
int x[L], y[L];
int getInt(){
  int c, r=0;
  while(isspace(c=fgetc(stdin)));
  do
    r=r*10+c-'0';
  while(isdigit(c=fgetc(stdin)));
  return r;
}
int main(){
  freopen("stergeri.in", "r", stdin);
  freopen("stergeri.out", "w", stdout);
  int m, k, i;
  m=getInt();
  m=getInt();
  k=getInt();
  for(i=0; i<m; i++){
    x[i]=getInt();
    y[i]=getInt();
  }
  for(i=m-1; i>=0; i--)
    if(k>=x[i])
      k=k+y[i]-x[i]+1;
  printf("%d\n", k);
  return 0;
}