#include <cstdio>
#include <iostream>
#include <sstream>
#include <fstream>
#include <iomanip>
#include <algorithm>
#include <cmath>
#include <string>
#include <vector>
#include <list>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <bitset>
#include <numeric>
#include <limits>
#include <climits>
#include <cfloat>
#include <functional>
using namespace std;

int main()
{
    long long a, b, t;
    cin >> a >> b >> t;

    long long ans = INT_MAX;
    for(int i=0; i<2; ++i){
        for(int j=0; j<100000; ++j){
            long long x = a * j;
            long long y = max(0LL, t - x);
            long long cost = x + (y + b - 1) / b * b;
            ans = min(ans, cost);
        }
        swap(a, b);
    }
    cout << ans << endl;

    return 0;
}