#include<iostream>
using namespace std;
int main()
{
    int n;
    cin>>n;
    try{
        if(n<1 || n>10){
            throw"Invalid input";
        }
        sum+=grade;
    }
    double gpa = sum/n;
    cout<<gpa;
}
catch(const char* a){
    cout<<a;
}
return 0;
}