Currency Exchange
Time Limit: 1 Second Memory Limit: 32768 KB
Several currency exchange points are working in our city. Let us suppose that
each point specializes in two particular currencies and performs exchange operations
only with these currencies. There can be several points specializing in the
same pair of currencies. Each point has its own exchange rates, exchange rate
of A to B is the quantity of B you get for 1A. Also each exchange point has
some commission, the sum you have to pay for your exchange operation. Commission
is always collected in source currency.
For example, if you want to exchange 100 US Dollars into Russian Rubles at the
exchange point, where the exchange rate is 29.75, and the commission is 0.39
you will get (100 - 0.39) * 29.75 = 2963.3975RUR.
You surely know that there are N different currencies you can deal with in
our city. Let us assign unique integer number from 1 to N to each currency.
Then each exchange point can be described with 6 numbers: integer A and B -
numbers of currencies it exchanges, and real RAB, CAB, RBA and CBA - exchange
rates and commissions when exchanging A to B and B to A respectively.
Nick has some money in currency S and wonders if he can somehow, after some
exchange operations, increase his capital. Of course, he wants to have his money
in currency S in the end. Help him to answer this difficult question. Nick must
always have non-negative sum of money while making his operations.
Input
The first line of the input file contains four numbers: N - the number of currencies,
M - the number of exchange points, S - the number of currency Nick has and V
- the quantity of currency units he has. The following M lines contain 6 numbers
each - the description of the corresponding exchange point - in specified above
order. Numbers are separated by one or more spaces. 1 <= S <= N <=
100, 1 <= M <= 100, V is real number, 0 <= V <= 10^3.
For each point exchange rates and commissions are real, given with at most two
digits after the decimal point, 10^-2 <= rate <= 10^2, 0 <= commission
<= 10^2.
Let us call some sequence of the exchange operations simple if no exchange point
is used more than once in this sequence. You may assume that ratio of the numeric
values of the sums at the end and at the beginning of any simple sequence of
the exchange operations will be less than 10^4.
Process to the end of file.
Output
If Nick can increase his wealth, output YES, in other case output NO to the output file.
Sample Input
3 2 1 10.0 1 2 1.00 1.00 1.00 1.00 2 3 1.10 1.00 1.10 1.00 3 2 1 20.0 1 2 1.00 1.00 1.00 1.00 2 3 1.10 1.00 1.10 1.00
Sample Output
NO YESSubmit
Source: Northeastern Europe 2001, Northern Subregion