import std.stdio;
import std.string;
import std.conv;
import std.algorithm;
import std.array;
import std.math;
import std.range;
import std.bigint;

void main() {
  auto l = readln.chomp.split.map!(to!long).array;
  long a = l[0], b = l[1], c = l[2];

  long lb = 1L, rb = 1e18.to!long, mid;

  if (c <= b * lb / a + lb - lb / a) lb.writeln;
  else {
    while (rb - lb > 1) {
      mid = (lb + rb) / 2;
      BigInt money = BigInt(b) * BigInt(mid / a) + BigInt((mid - mid / a));
      //writeln(money);

      if (money > BigInt(c)) {
        rb = mid;
      }
      else if (money < BigInt(c)) {
        lb = mid;
      }
      else {
        rb = mid;
        break;
      }
    }
  }

  // これlbですでにOKな場合だけでは…?
  //if (BigInt(b) * BigInt(lb / a) + BigInt((lb - lb / a)) >= BigInt(c)) rb = lb;

  rb.writeln;
}