#include <iostream>
using namespace std;
int main(){
int n,x;
double a=0;
cin>>n;
for(int i;i<=n;i++){
cin>>x;
if(x<=70){
a+=0.1;
}if(x<=140&&x>70){
a+=0.2;
}if(x<=210&&x>140){
a+=0.3;
}if(x<=280&&x>210){
a+=0.4;
}if(x<=350&&x>280){
a+=0.5;
}if(x<=420&&x>350){
a+=0.6;
}if(x<=490&&x>420){
a+=0.7;
}if(x<=560&&x>490){
a+=0.8;
}if(x<=630&&x>560){
a+=0.9;
}if(x<=700&&x>630){
a+=0.10;
}if(x<=770&&x>700){
a+=0.11;
}if(x<=840&&x>770){
a+=0.12;
}if(x<=910&&x>840){
a+=0.13;
}if(x<=980&&x>910){
a+=0.14;
}if(x<=1000&&x>980){
a+=0.15;
}
}
cout<<a;
return 0;
}
