#include <bits/stdc++.h>
using namespace std;
long long n, m, l, r, mid, k;
long long _ck(long long w) {
  long long i, j, tem = 0;
  for (i = 1; i <= min(n, w); i++) tem += min(m, (w - 1) / i);
  return tem;
}
int main() {
  scanf("%I64d%I64d%I64d", &n, &m, &k);
  l = 0;
  r = n * m + 1ll;
  while (l + 1 < r) {
    mid = (l + r) >> 1;
    if (_ck(mid) < k)
      l = mid;
    else
      r = mid;
  }
  printf("%I64d", l);
  return 0;
}
