1481: CF90 - A. Cableway
Description
The number of cablecars is divisible by three and they are painted three colors: red, green and blue, in such manner that after each red cablecar goes a green one, after each green cablecar goes a blue one and after each blue cablecar goes a red one. Each cablecar can transport no more than two people, the cablecars arrive with the periodicity of one minute (i. e. every minute) and it takes exactly $30$ minutes for a cablecar to get to the top.
All students are divided into three groups: $r$ of them like to ascend only in the red cablecars, $g$ of them prefer only the green ones and $b$ of them prefer only the blue ones. A student never gets on a cablecar painted a color that he doesn't like,
The first cablecar to arrive (at the moment of time $0$) is painted red. Determine the least time it will take all students to ascend to the mountain top.
Input
Output
Sample 1 Input
1 3 2
Sample 1 Output
34
At the moment of time 0 a red cablecar comes and one student from thergroup get on it and ascends to the top at the moment of time 30.
At the moment of time 1 a green cablecar arrives and two students from theggroup get on it; they get to the top at the moment of time 31.
At the moment of time 2 comes the blue cablecar and two students from thebgroup get on it. They ascend to the top at the moment of time 32.
At the moment of time 3 a red cablecar arrives but the only student who is left doesn't like red and the cablecar leaves empty.
At the moment of time 4 a green cablecar arrives and one student from theggroup gets on it. He ascends to top at the moment of time 34.
Thus, all the students are on the top, overall the ascension took exactly 34 minutes.
Sample 2 Input
3 2 1
Sample 2 Output
33