#include<fstream>
#include<algorithm>
using namespace std;

typedef struct lol {
      int x,y;  
}troll;

int i,n,m,x,y,poz;
troll a[100005];

int main()
{
  ifstream cin("stergeri.in");
  ofstream cout("stergeri.out");
  
  cin>>n>>m>>poz;
  for(i=m;i>=1;--i) cin>>a[i].x>>a[i].y;
  
  for(i=1;i<=m;++i)
  if(a[i].x<=poz) poz+=a[i].y-a[i].x+1;
  
  cout<<poz<<'\n';
    
 return 0;   
}