import std.algorithm, std.array, std.container, std.range, std.bitmanip;
import std.numeric, std.math, std.bigint, std.random, core.bitop;
import std.string, std.regex, std.conv, std.stdio, std.typecons;

void main()
{
  auto rd = readln.split.map!(to!int);
  auto a = rd[0], b = rd[1], t = rd[2];
  writeln(calc(a, b, t));
}

int calc(int a, int b, int t)
{
  if (t % a == 0) return t;

  auto ca = t / a + 1;
  auto cb = 0;
  auto ct = a * ca;

  bool[int] memo;
  memo[ct - t] = true;

  while (ca > 0) {
    ca -= (ct + b - t) / a;
    if (ca < 0) break;
    cb += 1;
    ct = a * ca + b * cb;
    if ((ct - t) in memo) break;
    memo[ct - t] = true;
  }

  return t + memo.keys.reduce!(min);
}