#include <iostream>
using namespace std;
int main()
{
	int m,n;
	cin >> m >> n;
	cout <<  (n-m)*30;
	
 } 
/**************************************************************
	Problem: 1320
	User: xiaomingze
	Language: C++
	Result: Accepted
	Time:7 ms
	Memory:2072 kb
****************************************************************/