#include<stdio.h>
long s,n,m,k,a,x,y,i;
int main()
{
	freopen("stergeri.in","r",stdin);
	freopen("stergeri.out","w",stdout);

	scanf("%ld %ld %ld",&n,&m,&k);
	a=k;
	for(i=1;i<=m;++i)
		{
			scanf("%ld %ld",&x,&y);
			if(a>=x)
				a=a+(y-x+1);
			s=s+(y-x+1);
		}

	printf("%ld",a);
	return 0;
}