#include <fstream>

using namespace std;

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

const int MAX_M = 100005;

int n, m, k, a[MAX_M], b[MAX_M];

int main()
{
	f >> n >> m >> k;
	for (int i = 1; i <= m; i++)
		f >> a[i] >> b[i];
	
	for (int i = m; i >= 1; i--)
		if (a[i] <= k)
			k += b[i] - a[i] + 1;
		
	g << k << '\n';
	
	return 0;
}