Problem:
Score : 100 points

Problem Statement

We have a sandglass that runs for X seconds. The sand drops from the upper bulb at a rate of 1 gram per second. That is, the upper bulb initially contains X grams of sand.

How many grams of sand will the upper bulb contains after t seconds?

Constraints

1≤X≤10^9

1≤t≤10^9

X and t are integers.

Input

The input is given from Standard Input in the following format:

X t

Output

Print the number of sand in the upper bulb after t second.

Sample Input 1

100 17

Sample Output 1

83

17 out of the initial 100 grams of sand will be consumed, resulting in 83 grams.

Sample Input 2

48 58

Sample Output 2

0

All 48 grams of sand will be gone, resulting in 0 grams.

Sample Input 3

1000000000 1000000000

Sample Output 3

0

Solution in Scala (2.11.7) (judge verdict: Accepted)

object Main{
  def main(args: Array[String]){
    val input=io.Source.stdin.getLines().mkString("\n")
    println(solve(input).trim())
  }

  def solve(input:String):String={
    val Array(x,t)=input.split(" ").map(_.toInt)
    Array(x-t,0).max.toString
  }
}