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 in advance