#include<bits/stdc++.h> #define ll long long using namespace std; struct node { int a,b; }; node a[100005]; int main() { // freopen("bamboo.in","r",stdin); // freopen("bamboo.out","w",stdout); int n; cin>>n; for(int i=1;i<=n;i++) { cin>>a[i].a>>a[i].b; } ll l=0,r=0; for(int i=1;i<=n;i++) { ll il=a[i].b,ir=a[i].a-a[i].b,lll=0,lr=0,rl=0,rr=0; lll=min(-il,l); lr=max(ir,r); rl=min(-ir,l); rr=max(il,r); if(lr-lll>=rr-rl) { l=lll; r=lr; } else { l=rl; r=rr; } } cout<<r-l; return 0; }