#include <fstream>

using namespace std;

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

int low[100005], high[100005], m, n, k, sol;

int main ()
{
	f >> n >> m >> k;
	sol = k;
	
	for (int i = 1; i <= m; i++)
	{
		f >> low[i] >> high[i];
	}
	
	while (m > 0)
	{
		if (low[m] <= sol)
			sol += (high[m] - low[m] + 1);
		m--;
	}
	
	g << sol;
	f.close();
	g.close();
	return 0;
}