#include<cstdio>
#include<iostream>
#include<vector>
#include<string>
#include<algorithm>
#include<map>
#include<set>
#include<queue>

#define reps(i,f,n) for(int i=f;i<int(n);i++)
#define rep(i,n) reps(i,0,n)
#define pb push_back

using namespace std;

#ifdef __BORLANDC__
	typedef __int64 ll;
#else
	typedef long long ll;
#endif

const int T = 1000;
const ll INF = 2111111111;
int visit[T];

int main(){
	
	ll a,b,t;
	cin>>a>>b>>t;
	
	
	if(b<a)swap(a,b);
	
	ll m = min(a,b);
	
	rep(i,T)visit[i] = 0;
	
	ll ans = INF;
	if(m<T){
		ll anum = (t+(a-1))/a;
		ll bnum = 0;
		while(1){
			ll A = anum*a;
			ll B = bnum*b;
			
			ll val = A+B;
			ans = min(ans, val);
			if(visit[(int)(val-t)]==1)break;
			visit[(int)(val-t)]=1;
			
			bnum++;
			anum = ((t-bnum*b)+(a-1))/a;
			
			if(t-bnum*b<0)break;
		}
	}else{
		for(int i=0;;i++){
			ll c = a*i;
			ll r = (max((ll)0, t-c)+(b-1))/b;
			ans = min(ans, c+r*b);
			if(c>=t)break;
		}
	}
	
	cout<<ans<<endl;
}