Codechef HS08TEST

#include <iostream>
using namespace std;

int main() {
    int number;
    float initial, left;

    cin >> number >> initial;

    if(number%5 != 0){
        cout << initial << endl;
    }

    else{
        if(number + 0.5 > initial){
            cout << initial << endl;
        }

        else{
            left = initial - number - 0.5;
            cout << left << endl;
        }
    }
    return 0;
}