#include <bits/stdc++.h>
using namespace std;
int m,n;
int main(){
    cin>>m>>n;
    cout<<(n-m)*30;
	return 0;
}
/**************************************************************
	Problem: 1320
	User: zengdongxin
	Language: C++
	Result: Accepted
	Time:15 ms
	Memory:2072 kb
****************************************************************/