#include <bits/stdc++.h>

using namespace std;

using ll = long long;
using ull = unsigned long long;
using ld = long double;
using P = pair<ll, ll>;
using tp = tuple<ll, ll, ll>;

template <class T>
using vec = vector<T>;
template <class T>
using vvec = vector<vec<T>>;

#define all(hoge) (hoge).begin(), (hoge).end()
#define en '\n'
#define rep(i, m, n) for(ll i = (ll)(m); i < (ll)(n); ++i)
#define rep2(i, m, n) for(ll i = (ll)(n)-1; i >= (ll)(m); --i)
#define REP(i, n) rep(i, 0, n)
#define REP2(i, n) rep2(i, 0, n)

constexpr long long INF = 1LL << 60;
constexpr int INF_INT = 1 << 25;
constexpr long long MOD = (ll)1e9 + 7;
//constexpr long long MOD = 998244353LL;
static const ld pi = 3.141592653589793L;

#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

template <class T>
inline bool chmin(T &a, T b) {
    if(a > b) {
        a = b;
        return true;
    }
    return false;
}

template <class T>
inline bool chmax(T &a, T b) {
    if(a < b) {
        a = b;
        return true;
    }
    return false;
}

//グラフ関連
struct Edge {
    int to, rev;
    ll cap;
    Edge(int _to, int _rev, ll _cap) : to(_to), rev(_rev), cap(_cap) {}
};

typedef vector<Edge> Edges;
typedef vector<Edges> Graph;

void add_edge(Graph &G, int from, int to, ll cap, bool revFlag, ll revCap) {
    G[from].push_back(Edge(to, (int)G[to].size(), cap));
    if(revFlag)
        G[to].push_back(Edge(from, (int)G[from].size() - 1, revCap));
}

void solve() {
    ll a, b, c, d;
    cin >> a >> b >> c >> d;
    if(b >= c * d) {
        cout << -1 << en;
        return;
    }

    ll ans = (a + (c * d - b - 1)) / (c * d - b);
    cout << ans << en;
}

int main() {
    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
    //cout << fixed << setprecision(10);

    // ll t;
    // cin >> t;
    // REP(i, t - 1) {
    //     solve();
    // }

    solve();

    return 0;
}

/* >>>>>Shwetal<<<<< */
#include <bits/stdc++.h>
#define int long long
#define f(i, begin, end) for (__typeof(end) i = (begin) - ((begin) > (end)); i != (end) - ((begin) > (end)); i += 1 - 2 * ((begin) > (end)))
#define inputArray(arr) f(i, 0, arr.size()) cin >> arr[i]
#define printArray(arr) f(i, 0, arr.size()) cout << arr[i] << ' '; cout << endl
#define endl '\n'
typedef long long ll;
const int mod = 1e9+7;
using namespace std;

void solve() {
    int x;
    cin >> x;
    int n = x;
    int a = 100;
    int rem = x % a;
    int div = x/a;
    if(rem == 0){
        cout << 100 << endl;
        return;
    }else{
        while(x % a != 0){
            div++;
            x = div * a;
            if(x % a == 0){
                cout << x - n << endl;
                return;
            }
        }
    }
    
}

int32_t main(){
    // freopen("input.txt","r",stdin); freopen("output.txt","w",stdout);
    ios::sync_with_stdio(0);
    cin.tie(0);
    int T = 1;
    // cin >> T;
    while(T--){
        solve();
        // if(solve())
            // cout << "YES" << endl;
        // else
            // cout << "NO" << endl;
    }
    return 0;
}