#include <stdio.h>
 
  int sum,plus,shousuu,total;
void avgup(int a){
	static int sum=0,plus=0;
	int shousuu,total;
	sum=sum+a;
    plus=plus+1;
    if(sum%plus==0){
    	shousuu=0;
    }
    if(sum%plus!=0){
    	shousuu=5;
    }
    total=sum/plus;
printf("%d.%d\n",total,shousuu);
}
 
int main(){
	int n,shousuu;
	while(1){
		scanf("%d",&n);
		if(n==0){
			break;
		}
              avgup(n);                       }
   return 0;
                                             }                                                 

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MSAyIDMgMA==

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