void main(){
  import std.stdio, std.string, std.conv, std.algorithm;
  import std.bigint;

  BigInt a, b, c; rd(a, b, c);

  bool ch(BigInt n){
    auto sum=(n/a)*b+(n-n/a);
    return sum>=c;
  }
  BigInt ng=0, ok=1_000_000_000_000_000_000*2;
  while(ok-ng>1){
    auto md=(ok+ng)/2;
    ch(md) ? ok : ng = md;
  }

  writeln(ok);
}


void rd(T...)(ref T x){
  import std.stdio, std.string, std.conv;
  auto l=readln.split;
  assert(l.length==x.length);
  foreach(i, ref e; x){
    e=l[i].to!(typeof(e));
  }
}