#include <stdio.h>

int c,ca,lit,cuv;

int main(){
	
	FILE*f1=fopen("text.in","r");
	
	fscanf(f1,"%c",&ca);
	if(ca>='A' && ca<='Z')
		ca+=32;
	if(ca>='a' && ca<='z')
		lit++;	
	
	while(fscanf(f1,"%c",&c)!=EOF){
		if(c>='A' && c<='Z')
			c+=32;
		if(ca>='a' && ca<='z')
			lit++;
		if((c<'a' || c>'z') && (ca>='a' && ca<='z'))
			cuv++;
		ca=c;
	}
	fclose(f1);	
	
	if((c<'a' || c>'z') && (ca>='a' && ca<='z'))
		cuv++;
	
	FILE*f2=fopen("text.out","w");
	fprintf(f2,"%d",lit/cuv);
	fclose(f2);
	
	return 0;
}