#include<bits/stdc++.h>
using namespace std;
#include<atcoder/all>
using namespace atcoder;
using ll = long long;
ll a,b,c;

ll f(ll n){
	ll nb = b*n;
	ll d = b - a;
	nb -= min(n,(nb-c)/d)*d;
	return nb;
}

void solve(){
	if(a>b)swap(a,b);
	ll n = (c+b-1)/b;
	ll m = (c+a-1)/a;
	ll ans = min(n*b,m*a);
	if(n<1000000){
		for(int i = 0;i<n;i++){//bがi個
			ll d = c - b*i;
			ll e = (d+a-1)/a;
			ans = min(ans,i*b+e*a);
		}
	}else if(m<1000000){
		for(int i = 0;i<m;i++){//aがi個
			ll d = c - a*i;
			ll e = (d+b-1)/b;
			ans = min(ans,i*a+e*b);
		}
	}else{
		for(int i = 0;i<1000000;i++){
			if(f(i+n)>=c)
			ans = min(ans,f(i+n));
		}
	}
	cout<<ans<<endl;
}

signed main(){
	cin.tie(nullptr);
	ios::sync_with_stdio(false);
	cin >> a >> b >> c;
	solve();
}