#include<bits/stdc++.h>
#include<cmath>
#define pb push_back
#define ld long double
#define mp make_pair
#define vl vector<ll> 
#define vd vector<double>
#define vld vector<long double>
#define ll long long int
#define pl pair<ll, ll>
#define all(a) a.begin(), a.end()
#define forr(i, n) for(ll i=0; i<n; i++) 
#define forr1(i, n) for(ll i=1; i<=n; i++)
using namespace std;
const ld PI =3.1415926535897923846;
const ll MOD = 1000000007;
const ll N=998244353;
ll power(ll x,ll n){ll res=1;while(n>0){if(n&1) res=res*x%MOD;x=x*x%MOD;n>>=1;}return res;}
ll modinverse(ll a){return power(a, MOD-2);}
void solve()
{
    ll x, y, z;
    cin>>x>>y>>z;
    if(y%x==0)
    {
        cout<<((y/x)*z)-1<<endl;
    }
    else
    {
        ll low=0, high=(ll)1e8;
        double eps=1.0/1e6;
        ll ans=0;
        ll count=0;
        while(count++<=100)
        {
            ll mid=low+(high-low)/2;
            double hump=(1.0*mid)/z;
            double bump=(1.0*y)/x;
            if(bump-hump>eps)
            {
                ans=mid;
                low=mid;
            }
            else
            {
                high=mid;
            }
        }
        cout<<ans<<endl;
    }
}
int main()
{
    #ifndef ONLINE_JUDGE
        // for getting input from input.txt
        freopen("input.txt", "r", stdin);
        // for writing output to output.txt
        freopen("output.txt", "w", stdout);
    #endif
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    ll test=1;
    //cin>>test;
    while(test--)
    {
        solve();
    }
    cerr << "Time : " << 1000 * ((double)clock()) / (double)CLOCKS_PER_SEC << "ms\n";
}
#line 1 "A.cpp"
#include <bits/stdc++.h>
using namespace std::literals::string_literals;
using i64 = std::int_fast64_t;
using std::cout;
using std::cerr;
using std::endl;
using std::cin;

#if defined(DONLINE_JUDGE)
	#define NDEBUG
#elif defined(ONLINE_JUDGE)
	#define NDEBUG
#endif

template<typename T> std::vector<T> make_v(size_t a){return std::vector<T>(a);}
template<typename T, typename... Ts> auto make_v(size_t a, Ts... ts){
  return std::vector<decltype(make_v<T>(ts...))>(a, make_v<T>(ts...));
}

int main() {
	int x, y, z; scanf("%d%d%d", &x, &y, &z);

	for(int i = 1e6; i >= 0; i--) {
		if(y * z <= x * i) continue;
		printf("%d\n", i);
		return 0;
	}

	#ifndef NDEBUG
	cout << "test" << endl;
	#endif
	return 0;
}
