uva 573

#include<stdio.h>

int main()
{
    float  day , ih , dc,H ,U , D, F,sliding;
    while(scanf("%f%f%f%f",&H,&U,&D,&F) && H){
        day = 1 ;
        ih  = 0 ;
        dc = U;
        sliding = U * F /100 ;
    while(1)
    {
       ih += dc ;
       if(ih>H){printf("success on day %.0f
",day) ; break;}
       ih -= D ;
       if(ih< 0){printf("failure on day %.0f
",day) ; break;}
       dc-= sliding ;
       if( dc < 0 ) dc = 0 ;
       day++;
    }
    }
    return 0 ;
}