#include <algorithm>
#include <cmath>
#include <cstdio>
#include <functional>
#include <iostream>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <stack>
#include <string>
#include <vector>
using namespace std;
using ll = long long;
int main() {
  ll a;
  cin >> a;
  int ans = 10000;
  for(int i = 1; i < 100; i++) {
    for(int j = 1; j < 100; j++) {
      if(a <= pow(i, j)) {
        ans = min(ans, i * j);
      }
    }
  }
  cout << ans << endl;
  return 0;
}