#include<bits/stdc++.h>
using namespace std;
int main(){
	int a,b;
	cin>>a;
	if(a>=90){
		b=a*3;
	}else if(a<90&&a>=80){
		b=a*2;
	}else if(a<80&&a>=70){
		b=a;
	}else if(a<70){
		b=50;
	}
	cout<<b;
} 
/**************************************************************
	Problem: 1300
	User: toughuatao1
	Language: C++
	Result: Accepted
	Time:15 ms
	Memory:2072 kb
****************************************************************/