#include<bits/stdc++.h>
using namespace std;
#define ALL(x) begin(x),end(x)
#define rep(i,n) for(int i=0;i<(n);i++)
#define debug(v) cout<<#v<<":";for(auto x:v){cout<<x<<' ';}cout<<endl;
#define mod 998244353
using ll=long long;
const int INF=1000000000;
const ll LINF=1001002003004005006ll;
int dx[]={1,0,-1,0},dy[]={0,1,0,-1};
template<class T>bool chmax(T &a,const T &b){if(a<b){a=b;return true;}return false;}
template<class T>bool chmin(T &a,const T &b){if(b<a){a=b;return true;}return false;}

struct IOSetup{
    IOSetup(){
        cin.tie(0);
        ios::sync_with_stdio(0);
        cout<<fixed<<setprecision(12);
    }
} iosetup;
 
template<typename T>
ostream &operator<<(ostream &os,const vector<T>&v){
    for(int i=0;i<(int)v.size();i++) os<<v[i]<<(i+1==(int)v.size()?"":" ");
    return os;
}
template<typename T>
istream &operator>>(istream &is,vector<T>&v){
    for(T &x:v)is>>x;
    return is;
}

const ll m=100000;

signed main(){
    ll a,b,t;cin>>a>>b>>t;

    if(b<=m){
        vector<ll> v(a,0);

        for(ll tot=0;tot<=t;tot+=b) v[(t-tot)%a]=1;

        ll res=LINF;
        if(v[0]) res=t;
        rep(i,a)if(v[i]) chmin(res,t+a-i);
        cout<<res<<endl;
    }else{
        // a * u + b * v
        ll res=LINF,v;
        for(v=0;v*b<=t;v++){
            ll rem=t-v*b;
            ll u=(rem+a-1)/a;
            chmin(res,a*u+b*v);
        }
        chmin(res,v*b);
        cout<<res<<endl;
    }
    return 0;
}