#include <iostream>
#include <fstream>

using namespace std;

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

#define MaxN 100001

int N,M,K,A[MaxN],B[MaxN],i,rez;

int main()
{
    fin>>N>>M>>K;

    for (i=1; i<=M; i++)
    {
        fin>>A[i]>>B[i];
    }

    rez=K;

    for (i=M; i>=1; i--)
    {
        if (A[i]<=rez)
        {
           rez=rez+(B[i]-A[i]+1);
        }
    }

    fout<<rez;

    return 0;
}