#include <iostream>
#include <fstream>
#include <algorithm>

using namespace std;

ifstream fin ("stergeri.in");
ofstream fout ("stergeri.out");

const int NMAX=100005;
struct poz
{
    int st;
    int dr;
}v[NMAX];

int main()
{
    int n,k,m,i,total=0,dist;
    fin>>n>>m>>k;
    for(i=1;i<=m;i++)
        fin>>v[i].st>>v[i].dr;
    total=k;
    for(i=m;i>=1;i--)
    {
        if(total>=v[i].st)
        {
            dist=v[i].dr-v[i].st+1;
            total=total+dist;
        }
    }
    fout <<total<< endl;
    return 0;
}