题目描述

blablabla

样例

#include <iostream>
using namespace std;
const int N = 10001;
int main()
{
    int l, r;
    cin >> l >> r;
    int res = 0;
    for (int i = l; i <= r; i ++ )
        for (int j = i; j; j /= 10)
            if (j % 10 == 2)
                res ++ ;
    cout << res << endl;
    return 0;
}