#include <fstream>
using namespace std;
ifstream cin("stergeri.in");
ofstream cout("stergeri.out");
typedef struct interval {
                         int x,y;
                         };
interval A[100013];
int i,n,m,k;
int main()
{
 cin>>n>>m>>k;
 for (i=1;i<=m;++i) cin>>A[i].x>>A[i].y;
 for (i=m;i>=1;--i) 
     if (A[i].x<=k) k+=1+A[i].y-A[i].x;
 cout<<k;   
return 0;
}