#include <fstream>

using namespace std;

#define maxC 100005
#define LL long long


struct cut
{
	LL low, high;
};

LL N, M, K, sol;
cut x[maxC];


int main()
{
	ifstream f("stergeri.in");
	ofstream g("stergeri.out");
	
	f >> N >> M >> K;
	
	sol = K;
	
	for (LL i = M; i >= 1; -- i)
	{
		f >> x[i].low;
		f >> x[i].high;
	}
	
	for (LL i = 1; i <= M; ++ i)
		if ( sol > x[i].low )
		{
			sol += x[i].high - x[i].low;
			++ sol;
		}
	
	g << sol;
	
	return 0;
}