n,k=map(int,input().split())
print(max(0,3*n-k))#include <bits/stdc++.h>
using namespace std;
int main(){
ios::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
int exams, mark, ans=0;
cin>>exams>>mark;
ans = exams * 2;
ans = mark - ans;
if(ans < exams) cout<<exams - ans;
else cout<< 0;
return 0;
}
1302. Deepest Leaves Sum | 1209. Remove All Adjacent Duplicates in String II |
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973. K Closest Points to Origin | 969. Pancake Sorting |
967. Numbers With Same Consecutive Differences | 957. Prison Cells After N Days |
946. Validate Stack Sequences | 921. Minimum Add to Make Parentheses Valid |
881. Boats to Save People | 497. Random Point in Non-overlapping Rectangles |
528. Random Pick with Weight | 470. Implement Rand10() Using Rand7() |
866. Prime Palindrome | 1516A - Tit for Tat |
622. Design Circular Queue | 814. Binary Tree Pruning |
791. Custom Sort String | 787. Cheapest Flights Within K Stops |
779. K-th Symbol in Grammar | 701. Insert into a Binary Search Tree |
429. N-ary Tree Level Order Traversal | 739. Daily Temperatures |
647. Palindromic Substrings | 583. Delete Operation for Two Strings |
518. Coin Change 2 | 516. Longest Palindromic Subsequence |
468. Validate IP Address | 450. Delete Node in a BST |