#include <bits/stdc++.h>
#define syosu(x) fixed<<setprecision(x)
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> P;
typedef pair<double,double> pdd;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<double> vd;
typedef vector<vd> vvd;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<string> vs;
typedef vector<P> vp;
typedef vector<vp> vvp;
typedef vector<pll> vpll;
typedef pair<int,P> pip;
typedef vector<pip> vip;
const int inf=1<<30;
const ll INF=1ll<<60;
const double pi=acos(-1);
const double eps=1e-8;
const ll mod=1e9+7;
const int dx[4]={-1,0,1,0},dy[4]={0,-1,0,1};

ll A,B,N;

int main(){
	cin>>A>>B>>N;
	ll res=INF;
	if(N/B<10000000){
		for(ll i=0;(i-1)*B<N;i++){
			ll n=N-i*B;
			res=min(res,i*B+(n>0?(n+A-1)/A*A:0));
		}
	}
	else{
		vi a(A);
		for(int i=0;;i++){
			int I=(N-i*B)%A;
			if(a[I]) break;
			a[I]=1;
		}
		for(int i=0;i<A;i++) if(a[i]) res=min(res,N+(i?A-i:0));
	}
	cout<<res<<endl;
}