#include<stdio.h>
#define M 100001
int n,m,k;
long long xk;
struct vec{
	int x,y;
}a[M];
void read()
{
	int i;
	scanf("%d%d%d",&n,&m,&k);
	for(i=1;i<=m;i++)
		scanf("%d%d",&a[i].x,&a[i].y);
}
void solve()
{
	int i;
	xk=k;
	for(i=m;i>=1;i--)
		if(a[i].x<=xk)
			xk+=a[i].y-a[i].x+1;
	printf("%lld\n",xk);
}
int main()
{
	freopen("stergeri.in","r",stdin);
	freopen("stergeri.out","w",stdout);
	read();
	solve();
	return 0;
}