573 - The Snail

//
//  main.cpp
//  The Snail
//
//  Created by Panks on 23/05/12.
//  Copyright (c) 2012 __MyCompanyName__. All rights reserved.
//

#include <iostream>
#include <cmath>
using namespace std;
int main (int argc, const char * argv[])
{
    
    
    double h, u, d;
    int f;
    cin>>h>>u>>d>>f;
    
    while (h!=0) {
        double tmp=0;
        int count=0;
        double df=u*f/100.0;
        while (1) {
            tmp=tmp+u;
            count++;
            if(tmp>h){
                cout<<"success on day "<<count<<endl;
                break;
            }
            tmp-=d;
            if(tmp<0&&count>0){
                cout<<"failure on day "<<count<<endl;
                break;
            }
            u=u-df;
            if (u<0) {
                u=0;
            }
        }
        
        cin>>h>>u>>d>>f;
    }
    
    return 0;
}