#include<stdio.h>
#include<string.h>
char n[500];
int main () {
	char end;
	int nr=0,nr2=0,nr3;
	FILE *in=fopen("text.in","r"), *out=fopen("text.out","w");
	end=fscanf(in,"%s",&n);
	nr++;
	nr3=strlen(n);
	while(end!=EOF){
		nr2+=strlen(n);
		if(((((n[nr3-2]-'0')<48)&&((n[nr3-2]-'0')>32)))||(((n[nr3-2]-'0')<65)&&((n[nr3-2]-'0')>57)))
			nr2--;
		end=fscanf(in,"%s",&n);
		nr++;
	}
	fprintf(out,"%d",nr2/nr);
	return 0;
}