\includegraphics{https://static.e-olymp.com/content/03/037e1055dcd5b6aac474829ace2e396c81b480d4.jpg} We Vasina grandmother in the garden growing many different fruit trees. One pear tree she planted on the birthday Wasi and said that as soon as it begins to bear fruit, Vasya must eat everything on it ripe pears. This year, first appeared Vasina pear fruit. Vasya counted all the fruit - they turned out to be \textbf{N} units. As soon as the first ripe pears, Vasya counted them and ate it. There were pieces of \textbf{K} - wonderful, huge and juicy. It turned out that every day to keep pace with \textbf{M} units more than the previous day. Grandma said that pears are very useful for Vasina health, and, consequently, every day Vasya should have as many as possible. Fortunately, the pears were so delicious that every day, eats all Vasya pospevshie in this day and glad that his grandmother. How many pears Vasya eat on the last day, when the mature \textbf{N}-th pear? \textbf{Input } In the input file lists the integers \textbf{N}, \textbf{K} and \textbf{M}. All the numbers do not exceed \textbf{1000000000}. \textbf{Output} Output one integer - the answer to the problem.