#include <stdio.h>
#include <bits/stdc++.h>
#include <atcoder/all>
using namespace atcoder;
using mint = modint;
using namespace std;
#define rep(i,n) for (int i = 0; i < (n); ++i)
#define Inf 2000000000


int main(){	
	
	int A,B,T;
	cin>>A>>B>>T;
	
	int n = (T+A-1)/A;
	int cur = n*A - T;
	int ans = cur;
	set<int> s;
	s.insert(cur);
	rep(i,n){
		cur -= A;
		if(cur<0)cur += B;
		ans = min(cur,ans);
		if(s.count(cur))break;
		s.insert(cur);
	}
	cout<<T+ans<<endl;
	
	return 0;
	
}