#include<stdio.h>
#define I "text.in"
#define O "text.out"
long int a,b,s,nr;
char c;
int main()
{
	FILE *f=fopen(I,"r");
	FILE *g=fopen(O,"w");
	a=-1;
	b=-1;
	s=0;
	nr=0;
	while(!feof(f)){
		fscanf(f,"%c",&c);
		if((c>='a' && c<='z') || (c>='A' && c<='Z')){
			if(a==-1){
				a=0;
				b=0;
			}
			else
				b+=1;
		}
		else{
			if(a!=-1){
				s=s+b-a+1;
				nr+=1;
			}
			a=b=-1;
		}
	}
	if(a!=-1){
		s=s+b-a+1;
		nr+=1;
	}
	fprintf(g,"%ld",s/nr);
	fcloseall();
	return 0;
}