1 1 2 2
1000000000 1000000000
1
 1 1 1000000000 1000000000
100 1000000000
1
 1 1 10 18
5 6
5
 2 1 1000000000 2000000000
111 999999999
101 999999998
1
 4 13 400 600
13 30
1 19
1 160
1 113
58 73 15 319 194 362 128 157 336 162 77 90 96
 1 15 100 200
283 8
30 58 16 45 80 82 55 95 24 23 86 28 51 47 20
 3 2 300 400
24 68
13 65
15 113
127 177
 1 1 2 1
1 10
1
 4 2 7 15
10 9
4 4
9 3
4 10
1 6
 2 1 1000000000 2000000000
111 1000000000
101 1000000000
5
 2 1 1000000000 2000000000
111 999999998
101 999999998
1
 1 1 1000000000 1000000000
1 1000000000
1

1000000000
 -1
 5
 111
 1
 -1
 -1
 -1
 4
 101
 -1
 -1

#include <bits/stdc++.h>
using namespace std;
int main() {
  long long left, right, mid, num, k1, mi, n, m, i, k;
  while (cin >> n >> m >> k) {
    left = 1;
    right = n * m;
    while (left <= right) {
      mid = (left + right) / 2 - 1;
      num = 0;
      for (i = 1; i <= n; ++i) {
        mi = min(m, mid / i);
        num += mi;
      }
      if (k > num) {
        left = mid + 1 + 1;
        k1 = mid;
      } else {
        right = mid;
      }
    }
    cout << k1 + 1 << endl;
  }
  return 0;
}
