# include <stdio.h>
int a[100010],b[100010],n,m,k,i,ok;
int main ()
{
freopen ("stergeri.in","r",stdin);
freopen ("stergeri.out","w",stdout);
scanf ("%i",&n);
scanf ("%i",&m);
scanf ("%i",&k);
for (i=0;i<m;i++)
scanf ("%i%i",&a[i],&b[i]);

ok=0;
while (ok==0)
{
ok=1;
for (i=0;i<m;i++)
if (a[i]!=-1)
if (a[i]<=k)
{
k=k+(b[i]-a[i]+1);
a[i]=-1;
ok=0;
}


}
ok=0;
while (ok==0)
{
ok=1;
for (i=0;i<m;i++)
if (a[i]!=-1)
if (a[i]<=k)
{
k=k+(b[i]-a[i]+1);
a[i]=-1;
ok=0;
}


}


printf ("%i",k);
return 0;
}