#include <fstream>

using namespace std;

ifstream cin( "stergeri.in" );
ofstream cout( "stergeri.out" );

struct Andrei {
	int x, y;
};

Andrei v[ 100010 ];
int n, m, k;

int main()
{
	cin >> n >> m >> k;
	for( int i = 0; i < m; i++ )
		cin >> v[ i ].x >> v[ i ].y;

	for( int i = m - 1; i >= 0; i-- )
		if( v[ i ].x <= k )
			k += ( v[ i ].y - v[ i ].x + 1 );

	cout << k << '\n';
	return 0;
}