#include <bits/stdc++.h>

using namespace std;

using u32 = uint32_t;

u32 count(u32 N) {
  u32 v = sqrt(N);
  vector<u32> sc(v + 1), lc(v + 1);
  for (u32 i = 1; i <= v; ++i) sc[i] = i - 1;
  for (u32 i = 1; i <= v; ++i) lc[i] = N / i - 1;
  for (u32 p = 2; p <= v; ++p) if (sc[p] != sc[p - 1]) {
    u32 c = sc[p - 1];
    u32 q = p * p;
    u32 w = v / p;
    for (u32 i = 1; i <= w; ++i) lc[i] -= lc[i * p] - c;
    u32 e = min(v, N / q);
    u32 m = N / p;
    for (u32 i = w + 1; i <= e; ++i) lc[i] -= sc[m / i] - c;
    for (u32 i = v; i >= q; --i) sc[i] -= sc[i / p] - c;
  }

  u32 ret = sc[int(cbrt(N))];
  for (u32 p = 2; p <= v; ++p) if (sc[p] != sc[p - 1]) {
    ret += lc[p] - sc[p];
  }
  return ret;
}

void solve() {
   u32 N; scanf("%u", &N);
   u32 hi = 1;
   for (; count(hi) < N; hi <<= 1);
   u32 lo = (hi >> 1) - 1;
   while (hi - lo > 1) {
     u32 mi = (lo + hi) >> 1;
     if (count(mi) < N) lo = mi;
     else hi = mi;
   }
   printf("%u\n", hi);
}

int main() {
  solve();
  return 0;
}