#include<bits/stdc++.h>
using namespace std;

int main(){
    int HP = 10000;
    int now_hp_cost = 0;
    int now_time = 0;
    while(now_hp_cost + 600 < HP){
        now_time += 2;
        now_hp_cost += 300;
    }
    if (now_hp_cost + 600 >= HP){
        now_time += 1;
        now_hp_cost += 600;
    }

    cout<< 60*now_time - (now_hp_cost - HP)/(600/60);
    
    return 0;
}