993 992 991
 100 1 10
 960 935 994
 99 8 99
 60 16 1
 759 10 258
 24 19 9
 196 169 144
 1000 999 1
 945 812 917
 1000 100 10
 500 300 300
 888 777 1000
 2 1 4
 24 12 12
 767 2 514
 2 1 2
 1000 1 1
 5 2 1
 70 32 1
 765 123 899
 17 7 10
 5 4 10
 888 777 888
 66 38 4
 1000 999 1000
 9 3 300
 244 87 4
 765 123 45
 1000 1 1000
 305 203 421
 100 10 1
 64 12 8
 894 1 999
 2 1 1
 18 14 10
 6 2 4
 888 777 1
 27 26 1
 2 1 3
 5 1 5
 7 3 200
 561 31 917
 17 10 7
 93 74 831

1
 990
 27
 1127
 3
 19325
 3
 24
 1
 151
 90
 200
 143
 4
 12
 196605
 2
 999
 2
 2
 4693
 15
 3
 127
 3
 2
 600
 8
 235
 999000
 212
 9
 35
 892107
 1
 3
 8
 1
 1
 3
 20
 267
 15678
 5
 214

#include <bits/stdc++.h>
using namespace std;
int a, b, c;
double noblok, ttime, db, cs, rb, t, sec, u;
vector<int> v;
bool fun(int sec) {
  db = sec * b;
  cs = db / a;
  rb = cs * b;
  t = abs(noblok - (rb + db));
  u = t / b;
  if ((noblok <= (rb + db)))
    return true;
  else if (cs >= u) {
    return true;
  } else
    return false;
}
int bs() {
  bool test;
  int l = 0, h = ((int)(v).size()), mid, flag = 0, w;
  while ((l < h) || ((l <= h) && (l <= ((int)(v).size())) && (l >= 0) &&
                     (h < ((int)(v).size())) && (h >= 0))) {
    mid = l + (h - l) / 2;
    test = fun(v[mid]);
    if (test == false) {
      l = mid + 1;
    } else if (test == true) {
      flag = 1;
      w = mid;
      h = mid - 1;
    }
  }
  cout << v[w] << endl;
}
int main() {
  int i;
  cin >> a >> b >> c;
  noblok = a * c;
  ttime = noblok / b;
  for (i = 1; i <= ttime; i++) {
    v.push_back(i);
  }
  bs();
}
