#include<fstream>
#define NMAX 100010

using namespace std;

ifstream f("stergeri.in");
ofstream g("stergeri.out");

int n, m, k, val, i, Sst[NMAX], Sdr[NMAX];

int main()
{
    f>>n>>m>>k; val=k;
    for (i=1; i<=m; ++i)
        f>>Sst[m-i+1]>>Sdr[m-i+1];

    for (i=1; i<=m; ++i)
    {
        if (Sst[i]<=val) val+=Sdr[i]-Sst[i]+1;
        //else
          //  if (Sst[i]<=val && Sdr[i]>=val) val+=val-Sst[i]+1;
    }
    g<<val<<"\n";
    f.close();
    g.close();
    return 0;
}