#include<fstream.h>
#include<math.h>

ifstream fin("stergeri.in");
ofstream fout("stergeri.out");

long n, i, x, y, m, k;

int main()
{
	 fin >> n >> m >> k;

	 for(i = 1; i <= m; i++)
	 {
		fin >> x >> y;

		if(x > y)
			k += (x - y + 1);
		else
			k += (y - x + 1);
	 }

	 fout << k << "\n";

	 return 0;
}