#include <stdio.h>
FILE *f = fopen("text.in","r");
FILE *g = fopen("text.out","w");
int nr,total,pred;
char c;
int main(){
	pred = 0; //predecesorul literei citite (0 daca nu a fost o litera, 1 daca a fost);
	while ( !feof(f)){
	fscanf(f,"%c",&c);
	if ( (c >= 65 && c <= 90) || (c >= 97 && c <=122) ){
		if ( !pred ) nr++, pred = 1;
		total++;
	} 
	else { if ( pred ) pred = 0; };
};
	fprintf(g,"%d.0",total/nr); 
}
//65->90 (litere mari)
//97->122 (litere mici);