#include <bits/stdc++.h>
using namespace std;
#define REP(i,a,n) for(int i=(a); i<(int)(n); i++)
#define rep(i,n) REP(i,0,n)
#define FOR(it,c) for(__typeof((c).begin()) it=(c).begin(); it!=(c).end(); ++it)
#define ALLOF(c) (c).begin(), (c).end()
typedef long long ll;
typedef unsigned long long ull;

ll gcd(ll a, ll b){return (b==0?a:gcd(b,a%b));}
ll lcm(ll a, ll b){return a/gcd(a,b)*b;}

bool check(ll A, ll B, ll K, ll X){
  ll n = X/A;
  ll m = X/B;
  ll o = X/lcm(A,B);

  return (n+m-o) < K;
}


int main(){
  ll A, B, K;
  cin >> A >> B >> K;

  ll lb = 0, ub = 5e18;
  while(ub-lb>1){
    ll mid = lb + (ub-lb)/2;

    if(check(A,B,K,mid)) lb = mid;
    else ub = mid;
  }

  cout << ub << endl;
  
  return 0;
}