Language: Java

import java.util.*; import java.io.*; import java.math.*;
public class Main{
	//Don't have to see. start------------------------------------------
	static class InputIterator{
		ArrayList<String> inputLine = new ArrayList<String>(1024);
		int index = 0; int max; String read;
		InputIterator(){
			BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
			try{
				while((read = br.readLine()) != null){
					inputLine.add(read);
				}
			}catch(IOException e){}
			max = inputLine.size();
		}
		boolean hasNext(){return (index < max);}
		String next(){
			if(hasNext()){
				return inputLine.get(index++);
			}else{
				throw new IndexOutOfBoundsException("There is no more input");
			}
		}
	}
	static HashMap<Integer, String> CONVSTR = new HashMap<Integer, String>();
	static InputIterator ii = new InputIterator();//This class cannot be used in reactive problem.
	static PrintWriter out = new PrintWriter(System.out);
	static void flush(){out.flush();}
	static void myout(Object t){out.println(t);}
	static void myerr(Object t){System.err.print("debug:");System.err.println(t);}
	static String next(){return ii.next();}
	static boolean hasNext(){return ii.hasNext();}
	static int nextInt(){return Integer.parseInt(next());}
	static long nextLong(){return Long.parseLong(next());}
	static double nextDouble(){return Double.parseDouble(next());}
	static ArrayList<String> nextStrArray(){return myconv(next(), 8);}
	static ArrayList<String> nextCharArray(){return myconv(next(), 0);}
	static ArrayList<Integer> nextIntArray(){
		ArrayList<String> input = nextStrArray(); ArrayList<Integer> ret = new ArrayList<Integer>(input.size());
		for(int i = 0; i < input.size(); i++){
			ret.add(Integer.parseInt(input.get(i)));
		}
		return ret;
	}
	static ArrayList<Long> nextLongArray(){
		ArrayList<String> input = nextStrArray(); ArrayList<Long> ret = new ArrayList<Long>(input.size());
		for(int i = 0; i < input.size(); i++){
			ret.add(Long.parseLong(input.get(i)));
		}
		return ret;
	}
	static String myconv(Object list, int no){//only join
		String joinString = CONVSTR.get(no);
		if(list instanceof String[]){
			return String.join(joinString, (String[])list);
		}else if(list instanceof ArrayList){
			return String.join(joinString, (ArrayList)list);
		}else{
			throw new ClassCastException("Don't join");
		}
	}
	static ArrayList<String> myconv(String str, int no){//only split
		String splitString = CONVSTR.get(no);
		return new ArrayList<String>(Arrays.asList(str.split(splitString)));
	}
	public static void main(String[] args){
		CONVSTR.put(8, " "); CONVSTR.put(9, "\n"); CONVSTR.put(0, "");
		
		solve();flush();
		
	}
	//Don't have to see. end------------------------------------------
	static void solve(){//Here is the main function
		ArrayList<String> one = nextIntArray();
		int N = one.get(0);
		int M = one.get(1);
		int L = 1;
		int R = N;
		for(int i = 0; i < M; i++){
			ArrayList<String> tmp = nextIntArray();
			L = Math.max(L, tmp.get(0));
			R = Math.min(R, tmp.get(1));
		}
		myout(Math.max(R - L + 1, 0));
	}
	//Method addition frame start




	//Method addition frame end
}


Compiler output:
Main.java:74: error: incompatible types: ArrayList<Integer> cannot be converted to ArrayList<String>
		ArrayList<String> one = nextIntArray();
		                                    ^
Main.java:75: error: incompatible types: String cannot be converted to int
		int N = one.get(0);
		               ^
Main.java:76: error: incompatible types: String cannot be converted to int
		int M = one.get(1);
		               ^
Main.java:80: error: incompatible types: ArrayList<Integer> cannot be converted to ArrayList<String>
			ArrayList<String> tmp = nextIntArray();
			                                    ^
Main.java:81: error: no suitable method found for max(int,String)
			L = Math.max(L, tmp.get(0));
			        ^
    method Math.max(int,int) is not applicable
      (argument mismatch; String cannot be converted to int)
    method Math.max(long,long) is not applicable
      (argument mismatch; String cannot be converted to long)
    method Math.max(float,float) is not applicable
      (argument mismatch; String cannot be converted to float)
    method Math.max(double,double) is not applicable
      (argument mismatch; String cannot be converted to double)
Main.java:82: error: no suitable method found for min(int,String)
			R = Math.min(R, tmp.get(1));
			        ^
    method Math.min(int,int) is not applicable
      (argument mismatch; String cannot be converted to int)
    method Math.min(long,long) is not applicable
      (argument mismatch; String cannot be converted to long)
    method Math.min(float,float) is not applicable
      (argument mismatch; String cannot be converted to float)
    method Math.min(double,double) is not applicable
      (argument mismatch; String cannot be converted to double)
Note: Main.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.
6 errors