#include<stdio.h>
int v[128000][2];
int main()
{
	freopen("stergeri.in", "r", stdin);
	freopen("stergeri.out", "w", stdout);
	int n, m, k, i;
	scanf("%d %d %d", &n, &m, &k);
	for (i=1; i<=m; i++)
		scanf("%d %d", &v[i][0], &v[i][1]);
	for (i=m; i>0; i--)
		if (v[i][0]<=k)
			k+=v[i][1]-v[i][0]+1;
	printf("%d", k);
	fclose(stdout);
	return 0;
}