#include<bits/stdc++.h> using namespace std; struct xxs{ int x,id; }a[300005]; bool cmp(xxs xx,xxs yy){ return xx.x<yy.x; } int b[300005],sum,maxx,minn,n,ans=1000000005; int main(){ cin>>n; for(int i=1;i<=n;i++){ cin>>a[i].x>>a[i+n].x>>a[i+2*n].x; a[i].id=a[i+n].id=a[i+2*n].id=i; } n*=3; sort(a+1,a+n+1,cmp); for(int l=1,r=1;r<=n;r++){ if(b[a[r].id]==0){ sum++; } b[a[r].id]++; while(b[a[l].id]>1){ b[a[l].id]--; l++; } if(sum==n/3){ ans=min(ans,a[r].x-a[l].x); } } cout<<ans; }