#include <iostream>
#include <fstream>

using namespace std;

#define Nmax 100005

int N, M, K;

int x[Nmax], y[Nmax];

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

    f >> N >> M >> K;

    for ( int i = 1; i <= M; ++i )
            f >> x[i] >> y[i];

    for ( int i = M; i >= 1; i-- )
    {
        if ( x[i] > K )
                continue;

        K += y[i] - x[i] + 1;
    }

    g << K << "\n";

    f.close();
    g.close();

    return 0;
}