#include <fstream>
#include <algorithm>
using namespace std;
ifstream fin("stergeri.in");
ofstream fout("stergeri.out");
int n,m,k;
struct Slayer
{
    int x,y;
};
Slayer v[100004];
int main()
{
    fin>>n>>m>>k;
    for(int i=1;i<=n;i++)
        fin>>v[i].x>>v[i].y;
    for(int i=m;i>0;i--)
    {
        if(v[i].x<=k)
        {
            k+=(v[i].y-v[i].x+1);
        }
    }
    fout<<k;
    return 0;
}