#include<bits/stdc++.h>
using namespace std;
int main(){
    int p,c;
    cin>>p;
    if(p>=90)c=3*p;
    else if(p>=80&&p<90)c=2*p;
    else if(p>=70&&p<80)c=1*p;
    else c=50;
    cout<<c;
}
/**************************************************************
	Problem: 1300
	User: chenmingyu
	Language: C++
	Result: Accepted
	Time:14 ms
	Memory:2072 kb
****************************************************************/