#include<algorithm>
#include<cmath>
#include<cstdio>
#include<functional>
#include<iomanip>
#include<iostream>
#include<map>
#include<queue>
#include<set>
#include<string>
#include<utility>
#include<vector>

using namespace std;
typedef long long ll;
const ll mod = 1000000007;
#define rep(i,n) for(int i=0;i<n;i++)
#define repl(i,s,e) for(int i=s;i<e;i++)
#define reple(i,s,e) for(int i=s;i<=e;i++)
#define revrep(i,n) for(int i=n-1;i>=0;i--)
#define all(x) (x).begin(),(x).end()


bool cond(ll x, ll A, ll B, ll C)
{
	//A年経過したときにもらえるお小遣い = (A年目にもらえるB円) + (それまでのA-1年間にもらえる1円)
	ll unit = B + (A - 1);

	ll gain = unit * (x / A) + (x % A);

	return gain >= C;
}

int main()
{	
	ll A, B, C = 0;
	cin >> A >> B >> C;

	ll ub = 1000000000000000001;
	ll lb = -1;

	while (ub - lb > 1)
	{
		ll mid = (ub + lb) / 2;

		if(cond(mid, A, B, C)) 
		{
			ub = mid;
		}
		else
		{
			lb = mid;
		}
	}

	cout << ub << endl;
	return 0;
}