#include <iostream>

int main(){

    int input = 0;
    int gradeCount = 0;
    int gradeSum = 0;

    while (input >= 0) {

        std::cout << "Enter grade (-1 finish)\n";
        std::cin >> input;
        if (input > 0) {
            gradeCount++;
            gradeSum+=input;
            std::cout << "Grade " << input << "% added\n";
        }
    }

    std::cout << "Average GPA is " << gradeSum / gradeCount;

    return 0;
}