#include<stdio.h>
long n,a[100001],b[100001];
int main()
{
long m,k,i;
freopen("stergeri.in","r",stdin);
freopen("stergeri.out","w",stdout);
scanf("%ld%ld%ld",&n,&m,&k);
for(i=1;i<=m;i++)
  scanf("%ld%ld",&a[i],&b[i]);
for(i=m;i>=1;i--)
  if(a[i]<=k)
    k=k+b[i]-a[i]+1;
printf("%ld",k);
return 0;
}