代码:
#include <iostream>
#include <algorithm>
using namespace std;
typedef long long ll;
ll ans=1,num=1;
ll n;
int prime[15]={1,2,3,5,7,11,13,17,19,23,29,31,37,41};
void dfs(ll dk,ll nx,ll cnt,ll gs)
{
if(dk==12){if(nx>ans&&cnt>num||ans>=nx&&cnt>=num){ans=nx,num=cnt;}return;}
ll w=1;
for(int i=0;i<=gs;i++)
{
dfs(dk+1,nx*w,cnt*(i+1),i);
w*=prime[dk];
if(nx*w>n) break;
}
}
int main()
{
cin>>n;
dfs(1,1,1,20);
cout<<ans<<endl;
//cout << "Hello world!" << endl;
return 0;
}