Div2 518A

Difference between en1 and en2, changed 203 character(s)

Why double coins = (double)(k+l)/m and then ceil(coins) works ↵
And this one faila for case 28↵
↵
#include<bits/stdc++.h>↵
#define ll long long↵
using namespace std;↵
int main()↵
{↵
    ll n,m,k,l;↵
    cin>>n>>m>>k>>l;↵
↵
    ll coins = ceil((double)(k+l)/m);↵
↵
    if(k+l > n || coins*m > n)↵
    {↵
        cout<<"-1"<<endl;↵
    }↵
    else {↵
        cout<<coins<<endl;↵
    }↵
    //main();↵
↵
}↵
Why double coins = (double)(k+l)/m and then ceil(coins) works ↵
And this one faila for case 28↵
Thanks for help↵
Thanks in advance↵