#include <stdio.h>
int main()
{
    int n,i,score;
    int j=0;
    scanf("%d",&n);
    for (i=1;i<=n;i++){
        scanf("%d",&score);
    if(score>=60){
            j++;
        }} double k=(double)j/n*100;
    printf("%.2lf%%",k);
    return 0;
}