#include<bits/stdc++.h>
using namespace std;
int main()
{
    double a , b , c;
    cin >> a >> b >> c;
    a = a + b + c;
    a = a / 3;
    printf("%.3f",a);
    return 0;
}

6

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

#include<bits/stdc++.h>
using namespace std;
int main()
{
    double a , b , c;
    cin >> a >> b >> c;
    a = a + b + c;
    a = a / 3;
    printf("%.3f",a);
    return 0;
}

A

#include <cstdio>
using namespace std;
int main(){
    float a,b,c;
    scanf("%f%f%f",&a,&b,&c);
    printf("%.3f",(a+b+c)/3);
    return 0;
}

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

#include<bits/stdc++.h> using namespace std;

int main(){ double a,b,c;//定义a、b、c cin>>a>>b>>c;//输入a、b、c cout<<(a+b+c)/3;//输出a、b、c的平均值 return 0; }