#include <fstream>

using namespace std;

ifstream cin("stergeri.in");
ofstream cout("stergeri.out");
int a[100001], b[100001];
signed main() {
  int n, m, k;
  cin >> n >> m >> k;
  for (int i = 1; i <= m; i++) {
    cin >> a[i] >> b[i];
  }
  for (int i = m; i >= 1; i--) {
    if (a[i] <= k) {
      k += (b[i] - a[i] + 1);
    }
  }
  cout << k;
  return 0;
}