#include<stdio.h>

int main(){
    int N m1,m2,m3,m4,m5;
    scanf("%d %d %d %d %d %d", &N,&m1,&m2,&m3, &m4,&m5);
    int sum,avg;
    sum= m1+m2+m3+m4+m5;
    avg=(sum/5);
    if(sum < 0){
        printf("Invalid input");
        return 0;
    }
    printf("%d". avg);
    return 0;
    
}