#include<bits/stdc++.h>
using namespace std;

int main()
{
    double h,u,d,f,a,b,c,e,g,j,k,ih,th,hac,has,dc,ff;
    while(scanf("%lf %lf %lf %lf",&h,&u,&d,&f)==4)
    {
        if(h==0)
            break;
        ff=(u*f)/100;
        int day=0,flag=0;
        th=0;
        while(1)
        {
            day++;
            th+=u;
            u-=ff;
            if(u<0)
                u=0;

            if(th>h){
                cout<<"success on day "<<day<<endl;
                break;}
            th-=d;
            if(th<0){
                cout<<"failure on day "<<day<<endl;
                break;}
        }
    }
    return 0;
}