#include <stdio.h>

#define NMAX 100010

int N, M, K;

int xx[NMAX], yy[NMAX];

int main()
{
	int i;

	freopen("stergeri.in", "r", stdin);
	freopen("stergeri.out", "w", stdout);

	scanf("%d %d %d", &N, &M, &K);

	for (i = 1; i <= M; i++) scanf("%d %d", &xx[i], &yy[i]);

	for (i = M; i >= 1; i--) if (xx[i] <= K) K += yy[i] - xx[i] + 1;

	printf("%d\n", K);

return 0;
}