#include <stdio.h>

int main()
{
FILE *in = fopen("text.in","r");
FILE *out = fopen("text.out","w");

char c;
long long s=0,nr=0,a=-1,b=-1;

while (!feof(in))
{
fscanf(in,"%c",&c);
if (('a'<=c && c<='z') || ('A'<=c && c<='Z'))
{
if (a==-1) a=0,b=1;
else b++;
}
else
{
if (a!=-1)
{
s = s + b;
nr++;
}
a=-1;
b=-1;
}
}
fprintf(out,"%d",s/nr);
}