#pragma GCC optimize ("Ofast")
#include<bits/stdc++.h>
using namespace std;
inline int my_getchar_unlocked(){
  static char buf[1048576];
  static int s = 1048576;
  static int e = 1048576;
  if(s == e && e == 1048576){
    e = fread_unlocked(buf, 1, 1048576, stdin);
    s = 0;
  }
  if(s == e){
    return EOF;
  }
  return buf[s++];
}
inline void rd(long long &x){
  int k;
  int m=0;
  x=0;
  for(;;){
    k = my_getchar_unlocked();
    if(k=='-'){
      m=1;
      break;
    }
    if('0'<=k&&k<='9'){
      x=k-'0';
      break;
    }
  }
  for(;;){
    k = my_getchar_unlocked();
    if(k<'0'||k>'9'){
      break;
    }
    x=x*10+k-'0';
  }
  if(m){
    x=-x;
  }
}
struct MY_WRITER{
  char buf[1048576];
  int s;
  int e;
  MY_WRITER(){
    s = 0;
    e = 1048576;
  }
  ~MY_WRITER(){
    if(s){
      fwrite_unlocked(buf, 1, s, stdout);
    }
  }
}
;
MY_WRITER MY_WRITER_VAR;
void my_putchar_unlocked(int a){
  if(MY_WRITER_VAR.s == MY_WRITER_VAR.e){
    fwrite_unlocked(MY_WRITER_VAR.buf, 1, MY_WRITER_VAR.s, stdout);
    MY_WRITER_VAR.s = 0;
  }
  MY_WRITER_VAR.buf[MY_WRITER_VAR.s++] = a;
}
inline void wt_L(char a){
  my_putchar_unlocked(a);
}
inline void wt_L(long long x){
  int s=0;
  int m=0;
  char f[20];
  if(x<0){
    m=1;
    x=-x;
  }
  while(x){
    f[s++]=x%10;
    x/=10;
  }
  if(!s){
    f[s++]=0;
  }
  if(m){
    my_putchar_unlocked('-');
  }
  while(s--){
    my_putchar_unlocked(f[s]+'0');
  }
}
template<class T, class U> inline T GCD_L(T a, U b){
  T r;
  while(b){
    r=a;
    a=b;
    b=r%a;
  }
  return a;
}
template<class T, class U> inline T LCM_L(T a, U b){
  return a/GCD_L(a,b)*b;
}
int main(){
  long long A;
  rd(A);
  long long B;
  rd(B);
  long long K;
  rd(K);
  long long lm;
  long long res;
  lm =LCM_L(A, B);
  long long KL2GvlyY;
  long long Q5VJL1cS;
  long long e98WHCEY;
  KL2GvlyY = 0;
  Q5VJL1cS = 1000000000000000000LL;
  while(KL2GvlyY < Q5VJL1cS){
    if((KL2GvlyY + Q5VJL1cS)%2==0){
      e98WHCEY = (KL2GvlyY + Q5VJL1cS) / 2;
    }
    else{
      e98WHCEY = (KL2GvlyY + Q5VJL1cS - 1) / 2;
    }
    if( e98WHCEY/A + e98WHCEY/B - e98WHCEY/lm >= K ){
      Q5VJL1cS = e98WHCEY;
    }
    else{
      KL2GvlyY = e98WHCEY + 1;
    }
  }
  res =Q5VJL1cS;
  wt_L(res);
  wt_L('\n');
  return 0;
}
// cLay version 20210103-1 [bug fixed 1]

// --- original code ---
// {
//   ll @A, @B, @K, lm, res;
//   lm = lcm(A,B);
//   res = bsearch_min[ll,x,0,1d18]( x/A + x/B - x/lm >= K );
//   wt(res);
// }