#include <iostream>
#include <set>
using namespace std;
int main(){
  int a,b,t;cin>>a>>b>>t;
  set<int> A;
  for(int i = 0; t/b >= i; i++){
    if(A.count((t-b*i)%a))break;
    A.insert((t-b*i)%a);
  }
  int mn = a;
  for(auto x: A){
    if(x == 0)mn = x;
    else mn = min(mn,a-x);
  }
  cout << mn+t << endl;
}