#include <iostream>

using namespace std;
typedef long long ll;
ll gcd(ll a,ll b){
    if(a<b) swap(a,b);
    if(b==0) return a;
    return gcd(a%b,b);
}

ll solve(ll a,ll b,ll x){
    ll lcm = a*b/gcd(a,b);
    return x/a + x/b - x/lcm;
}

int main(){
    ll a,b,k; cin >> a >> b >> k;
    ll l = 1,r = 1000000000000000000;
    while(r - l>1){
        ll mid = (l + r)/2;
        if(solve(a,b,mid)>=k) r = mid;
        else l = mid;
    }
    cout << r << endl;
}