#include <iostream>
#include<array>
#include <bits/stdc++.h>
#include<string>
using namespace std;
int main ()



{
    double h=0,u=0,d=0,f=0,k=1;
    float c,m=0;
    cin>>h>>u>>d>>f;
    while(h!=0){
        c=u*(f/100);
        m=0;
        k=0;
        while(m>=0){
            k++;
            m+=u;
            if(m<=h) {

                    m-=d;
            }
            else {
                cout<<"success on day "<<k<<endl;
                break;
            }
           if(u>0) u-=c;
            else u=0;


        }
        if(m<0) cout<<"failure on day "<<k<<endl;
        cin>>h>>u>>d>>f;
    }


    return 0;
}