#include<iostream.h>
#include<stdio.h>
FILE *f=fopen("text.in","r"),*g=fopen("text.out","w");
 int main()
{
char x=0,a[1000000];
int nrl=0,nrc=0;
float ma;
while(!feof(f))
{
x++;
fscanf(f,"%c",&a[x]);
if(a[x]>='A'&&a[x]<='Z'||a[x]>='a'&&a[x]<='z')
nrl++;
else
if(a[x-1]>='A'&&a[x-1]<='Z'||a[x-1]>='a'&&a[x-1]<='z')
nrc++;
}
ma=nrl/(float)nrc;
fprintf(g,"%f",ma);
return 0;
}