#include <iostream>

using namespace std;

int main()
{
	double x, y, z;
	cin >> x >> y >> z;
	double a = y / x;
	for (double b = 1;; b++) {
		if (b / z >= a) {
			cout << int(b) - 1 << endl;
			return 0;
		}
	}
}
#include <bits/stdc++.h>
using namespace std;

using ld = long double;
using ll = long long;
using ull = unsigned long long;
using pii  = pair<int, int>;
using pll = pair<ll, ll>;
using vi = vector<int>;
using vll = vector<ll>;

#define max(p,q) ((p)>(q)?(p):(q))
#define min(p,q) ((p)<(q)?(p):(q))

#define rep(i,n) for (int i = 0, i##_len = (n); i < i##_len; i++)
#define rep1(i,n) for (int i = 1, i##_len = (n); i <= i##_len; i++)
#define repr(i,n) for (int i = ((int)(n)-1); i >= 0; i--)
#define rep1r(i,n) for (int i = ((int)(n)); i >= 1; i--)
#define repl(i,l,n) for (int i = (l), i##_len = (n); i < i##_len; i++)

#define sz(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()

#define SORT(v, n) sort(v, v + n);
#define VSORT(v) sort(v.begin(), v.end());
#define RSORT(x) sort(rall(x));
#define mp make_pair

#define has_key(m, k) (m.find(k) != m.end())

#define INF (1e9)
#define EPS (1e-7)

// 総数を1000000007（素数）で割った余り
const ll mod = (1000000007);

ull gcd(ull a, ull b) { return b ? gcd(b, a % b) : a; }
ull lcm(ull a, ull b) { return a / gcd(a, b) * b; }


int main(){
    long long a;
    scanf("%lld",&a);
    long long b;
    scanf("%lld",&b);
    long long c;
    scanf("%lld",&c);
    long long d;
    scanf("%lld",&d);

    cout << b - c << endl;

    return 0;
}
