#include<bits/stdc++.h>
using namespace std;
int main(){
	int m,n,f;
	cin>>m>>n;
	f=(n-m)*30;
	cout<<f; 
}		


/**************************************************************
	Problem: 1320
	User: tonghuawei
	Language: C++
	Result: Accepted
	Time:14 ms
	Memory:2072 kb
****************************************************************/