C++ :

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int main()
{
	int l,r,ans=0;
	cin>>l>>r;
	char s[11];
	for(int i=l;i<=r;i++)
	{
	
	  sprintf(s,"%d",i);
	 int j=strlen(s);
	 for(int a=0;a<=j;a++)
	   if(s[a]=='2')ans++;
    }
    cout<<ans;
}

Pascal :

var
  l,r:1..10000;
  i,j,h,c:longint;
  s:string;
begin
  {assign(input,'two.in');
  assign(output,'two.out');
  reset(input);
  rewrite(output);}
  readln(l,r);
  c:=0;
  for i:=l to r do
    begin
      str(i,s);
      h:=length(s);
      for j:=1 to h do
        if s[j]='2'
          then c:=c+1;
    end;
  writeln(c);
 { close(input);
  close(output);}
end.

Java :

public class Main {
	public static void main(String[] args) {
		java.util.Scanner in = new java.util.Scanner(System.in);
		while (in.hasNext()) {
			int counted=0;
			int a=in.nextInt();
			int b=in.nextInt();
			for(int i=a;i<=b;i++)
			{
				String s=""+i;
				counted=reckon(s,counted);
			}
			System.out.println(counted);
		}
		in.close();
	}

	private static int reckon(String s, int counted) {
		for(int i=0;i<s.length();i++)
		{
			if(s.charAt(i)=='2')
				counted++;
		}
		return counted;
	}
}