#include<stdio.h>

int m,n,k;
struct inter
{
	int x,y;
};
inter v[1000006];

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",&v[i].x,&v[i].y);
	for(i=m;i>=1;i--)
		if(v[i].x<=k)
			k+=v[i].y-v[i].x+1;
	printf("%d\n",k);	
	return 0;
}