#include<iostream>

#include<map>

#include<algorithm>

#include<vector>

using namespace std;

int main(){

unsigned long long int i,divsum,maxcount=0,ans,j,res=0;

map<unsigned long long int,unsigned long long int> mp;

vector<unsigned long long int> v;

v.assign(1000001,1);

for(i=2;i<=500000;i++){

for(j=i+i;j<=1000000;j+=i) v[j]+=i;

}

for(i=4;i<=1000000;i++){

ans=i;

divsum=i;

mp.clear();

while(mp.find(divsum)==mp.end()){

mp[divsum]=divsum;

if(divsum<i) ans=i;

if(divsum>1000000) break;

divsum=v[divsum];

}

if(divsum<=1000000 && divsum==i && mp.size()>maxcount){

maxcount=mp.size();

res=ans;

}

}

cout<<res;

}