#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 l = n,r = n*100;
	while(r-l>1){
		ll m = (l+r)/2;
		if(f(m)<f(m+1)){
			r = m;
		}else{
			l = m;
		}
	}
	cout<<min(f(l),f(r))<<endl;
}

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