Рельсы

/*#include <iostream>
#include <string>
#include <map>
using namespace std;

int main()
{
    int age, i, n;
    string s;
    map<int, int> a;
    cin >> n;
    for (i = 0; i < n; i++)
    {
        cin >> age;
        a[age]++;
    }
    map<string, int>::iterator iter;
    for (iter = a.begin(); iter != a.end(); iter++)
        cout << iter->first << " " << iter->second << endl;
    system("pause");
    return 0;
}*/
#define _USE_MATH_DEFINES
#include <iostream>
#include <string>
#include <map>
#include <set>
#include <algorithm>
#include <vector>
#include <stdio.h>
#include <cmath>
#include <math.h>
#include <queue>
#include <stack>
#include <climits>
#include <deque>
#include <ctime>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef unsigned int ui;

#define mh() make_heap()
#define poph() pop_heap()
#define pushh() push_heap()
#define sor(n) n.begin(), n.end()
#define rsor(n) n.rbegin(), n.rend()
#define mp make_pair
#define files freopen("input.txt", "rt", stdin); freopen("output.txt", "wt", stdout)
#define p(T) pair<T,T>
#define znac(l) abs(l)/l
const ll ok = ll(1e9 + 7);

int main()
{
#ifndef ONLINE_JUDGE
    files;
#endif
    ll n;
    cin >> n;
    double S, l;
    cin >> S >> l;
    ll k = S / l;
    ll answ = k*n;
    double os = S - k*l;
    if (os > 1e-9)
    {
        double p = l / os;
        k = ll(p+1e-9);
        if (k >= n)
            answ += 1;
        else
            answ += n/k+bool(n%k);
    }
    cout << answ;
    return 0;
}