107

#include <iostream>
using namespace std;
long long getAmount(long long sum){
    long long amount = 0;
    amount = sum/100*100;
    sum%=100;
    amount+=(sum/30)*20;
    sum%=30;
    amount+=sum/2;
    return amount;
}
int main(){
    long long x,y,sum=0;
    cin>>x;
    long long startingX=x;
    if(x>=100){
        y = x/100;
        x%=100;
        sum+=100*y;
        if(getAmount(sum)>startingX){
            cout<<sum<<endl;
            return 0;
        }
    }
    if(x>=20){
        y = x/20;
        x%=20;
        if(30*y>100){
            sum+=100;
            if(getAmount(sum)>startingX){
                cout<<sum<<endl;
                return 0;
            }
        }
        else sum+=30*y;
        if(getAmount(sum)>startingX){
            cout<<sum<<endl;
            return 0;
        }
    }
    if(x>0){
        if(x*2>100) sum+=100;
        else if(x*2>30) sum+=30;
        else sum+=x*2;
    }
    cout<<sum<<endl;
    return 0;
}