UVa 573

#include<stdio.h>
int main()
{
    double h,u,d,f,p,i,t;
    while(1){
        scanf("%lf %lf %lf %lf",&h,&u,&d,&f);
        if(h==0)
            break;
        p=u*(f/100);
        i=0;
        t=0;
        while(1){
            i=i+1;
            t=t+u;
            u=u-p;
            if(u<0)
                u=0;
            if(t>h){
                printf("success on day %.0lf\n",i);
                break;
            }
            t=t-d;
            if(t<0){
                printf("failure on day %.0lf\n",i);
                break;
            }
        }
    }
    return 0;
}