Please help me I got WA test13
I had done everything plz help.
Thank you beforehand.


//1607. Taxi
#include <iostream>
using namespace std;
int main()
{
    int a,b,c,d,i,m;
    cin>>a>>b>>c>>d;
    if(a>=c)
        cout<<a<<endl;
    else
    {
        if(b<d)
            m=b;
        else
            m=d;
        for(i=1;c-d*(i-1)-a-b*i>m;i++);
        if(c-d*(i-1)-a-b*i>=0)
            cout<<a+b*i<<endl;
        else
            cout<<c-d*(i-1)<<endl;
    }
    return 0;
}