#include<fstream.h>
ifstream f("stergeri.in");
ofstream g("stergeri.out");
long n,m,k,x,y,j,l,a[100001],b[100001];
int main()
{
f>>n>>m>>k;
for(int i=1;i<=m;i++)
	{f>>x>>y;
	 if(k>=x)
		 k+=y-x+1;
	 else
		{while(x<a[j])
			{a[j+1]=a[j];b[j+1]=b[j];j--;}
		 l++;a[j+1]=x;b[j+1]=y;j=l;
		}
	}
for(j=1;j<=l;j++)
	if(a[j]<=k)
		k+=b[j]-a[j]+1;
g<<k;
return 0;
}