00573.cpp

/*
  Solution a problem 573 at UVA's online judge
 */
#include<iostream>
#include<algorithm>
using namespace std;

int main()
{
    int H,U,D,F;
    while(1)
    {
	/*
	  H is the height of the well
	  U is the distance the snail can climb each day
	  D is the distance slid during the night
	  F is the fatigue factor
	*/
	cin >> H >> U >> D >> F;
	if(H == 0)
	    break;
	//Multiply all numbers by 100 so that doubles never have to be used
	H*=100; U*=100; D*=100;

	//Calculate the base fatigue distance
	F = U / 100 * F;
	
	int climbed = 0; //Distance climbed
	int day = 0;
	while(climbed <= H && climbed >= 0)
	{
	    climbed += max(U - day*F,0);
	    day++;
	    if(climbed > H)
		break;
	    climbed -= D;
	}
	if(climbed > H)
	    cout << "success on day " << day;
	else
	    cout << "failure on day " << day;
	cout << endl;
    }
    return 0;
}