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 C# (Mono 4.6.2.0) (judge verdict: Accepted)


using System;
using System.Collections.Generic;
using System.Linq;

public class Hello{
    public static Scanner sc = new Scanner();
    public static void Main(){
        var x = sc.NextInt();
        var t = sc.NextInt();
        
        if(x<t){
            Console.WriteLine(0);
        }else{
            Console.WriteLine(x-t);
        }
    }
}

public class Scanner{
    private string line;
    private string[] token;
    private int cursole = 0;
    
    public string ReadLine(){
        line = Console.ReadLine();
        token = line.Split(' ');
        cursole = 0;
        return line;    
    }
    
    public string Next(){
        if(token == null) ReadLine();
        if(token.Length <= cursole) ReadLine();
        var ret = token[cursole];
        ++cursole;
        return ret;
    }

    public IEnumerable<double> NextDoubleList(){
        return NextList().Select(s => Double.Parse(s));
    }

    public int NextInt(){return Int32.Parse(Next());}
    
    public long NextLong(){return Int64.Parse(Next());}

    public double NextDouble(){return Double.Parse(Next());}

    public IEnumerable<string> NextList(){
        ReadLine();
        cursole = Int32.MaxValue;
        return token;
    }
    
    public IEnumerable<int> NextIntList(){
        return NextList().Select(s => Int32.Parse(s));
    }
}

public static class Extension{
    public static IEnumerable<int> To(this int from, int to){
        return Enumerable.Range(from, to);
    }

    public static void Times(this int times, Action<int> action){
        0.To(times).ToList().ForEach(x => action(x));
    }
}