C :

#include<stdio.h>
int main()
{
int a,b,c;
double s;
scanf("%d%d%d",&a,&b,&c);
s=(a+b+c)/3.0;
printf("%.3lf",s);
return 0;
}

C++ :

#include<bits/stdc++.h>
using namespace std;
int main(){
   int a,b,c;
   cin>>a>>b>>c;
   cout<<fixed<<setprecision(3)<<(a + b +c) / 3.0 <<endl; 

	return 0;
}

Java :

import java.util.Scanner;

public class Main {
	public static void main(String[] agse) {
		Scanner sc =new Scanner(System.in);
		int a =sc.nextInt();
		int b =sc.nextInt();
		int c =sc.nextInt();
		double g =(a+b+c)/3.0;
		System.out.println(String.format("%.3f",g));
	}
}

Python :

n = input().split()
x = int(n[0])
y = int(n[1])
z = int(n[2])
a = x + y + z
print("%.3f" % (a / 3))