#include<stdio.h>
long long nr,sum;

void read ()
	{
	FILE *f=fopen("text.in","r");
	char c;
	while ( !feof(f) )
		{
		fscanf(f,"%c",&c);
		if ('a'<=c&&c<='z'||'A'<=c&&c<='Z')
			{
			nr++;
			while ('a'<=c&&c<='z'&&!feof(f)||'A'<=c&&c<='Z'&&!feof(f))
				{
				sum++;
				fscanf(f,"%c",&c);
				}
			}
		}
	fclose(f);
	}

int main ()
{
read ();
FILE *f=fopen("text.out","w");
fprintf(f,"%lld",sum/nr);
fclose(f);
return 0;
}