#include<bits/stdc++.h>
using namespace std;
int main(){
	int a,b;
	cin>>a>>b;
	cout<<(b-a)*30;
	return 0;
} 
/**************************************************************
	Problem: 1320
	User: fuhoubin
	Language: C++
	Result: Accepted
	Time:8 ms
	Memory:2072 kb
****************************************************************/