C++ :

#include<iostream>
using namespace std;
int main()
{
	int L,R,x,s,a;
	cin>>L>>R;
	x=0;
	for(int i=L;i<=R;i++)
	{
		s=i;
		while(s!=0)
		{
		a=s%10;
		if(a==2) x=x+1;
		s=s/10;
		}
	}
	cout<<x<<endl;
	return 0;
}

Python :

# coding=utf-8
a,b=map(int,input().split())
c=0
for i in range(a,b+1):
    while i>0:
        if i%10==2:
            c+=1
        i//=10
print(c)