#include <fstream>

using namespace std;

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

int n, m, k, sol, i, a, b, anta, antb;

int main()
{
    fin>>n>>m>>k;
    sol=k;
    for(i=1;i<=m;i++){
        fin>>a>>b;
        if(a<=k)
            sol=b+1+(k-a)+(antb-anta+1);
        anta=a;
        antb=b;

    }
    fout<<sol;


    return 0;
}