#include <iostream>
#include <fstream>

using namespace std;

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

int main() {
    int n, m, k;
    fin >> n >> m >> k;
    int sum = 0;
    for (int i = 0; i < m; i++) {
        int x, y;
        fin >> x >> y;
        sum += y - x  +1;
        if (x < k) {
            k += sum;
            sum = 0;
        }
    }
    fout << k + sum << '\n';


    return 0;
}