#include <iostream>

using namespace std;

int d[8] = {0,1500,4500,9000,35000,55000,80000,1000000};
double tax[8] = {0,0.03,0.1,0.2,0.25,0.3,0.35,0.45};
int pay;

int get(int x){
    if(x <= 3500) return x;
    int pay = x - 3500;

    double res = 0;
    for(int i = 1;i <= 7;i++){
        if(d[i] <= pay){
            res += (d[i] - d[i - 1]) * tax[i];
        }else {
            res += (pay - d[i - 1]) * tax[i];
            break;
        }
    }
    return x - res;
}

int main(){
    int t;
    cin >> t;

    int l = t,r = t * 2;
    while(l < r){
        int mid = (l + r) >> 1;
        if(get(mid) >= t) r = mid;
        else l = mid + 1;
    }
    cout << l << endl;

    return 0;
}