# include <stdio.h>
long int a[5000],b[5000],i,j,m,n,k,aux;
int main ()
{
freopen ("stergeri.in","r",stdin);
freopen ("stergeri.out","w",stdout);
scanf ("%li",&n);
scanf ("%li",&m);
scanf ("%li",&k);
for (i=0;i<m;i++)
{
scanf ("%li",&a[i]);
scanf ("%li",&b[i]);
}
for (i=0;i<m-1;i++)
for (j=i+1;j<m;j++)
if (a[i]>a[j])
{
aux=a[i];
a[i]=a[j];
a[j]=aux;
aux=b[i];
b[i]=b[j];
b[j]=aux;
}
for  (i=0;i<m;i++)
if (k>=a[i])
k=k+(b[i]-a[i]+1);
else
break;
printf ("%li",k);
return 0;
}