calculate sum of total of 3 subjects in C++

 #include<iostream>

#include<iomanip>

using namespace std;

int main() {

    int science;

    int english;

    int math;

    cout<<"enter science marks: ";

    cin>>science;

    cout<<"enter english marks: ";

    cin>>english;

    cout<<"enter math marks: ";

    cin>>math;

    int avg = (science+science+math)/3;

    cout<<"avg = "<<avg<<endl;

    return 0;

}