#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 ans = n*b;
	n--;
	for(int i = n;i<n+100000;i++){
		if(f(i)>=c){
			ans = min(ans,f(i));
		}
	}
	cout<<ans<<endl;
}

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