#include <stdio.h>

#define MAX 8192

int main(){
	FILE* fin=fopen("text.in","rb");
	FILE* fout=fopen("text.out","w");
	unsigned int t,p=0,cc=0,nc=0,ptr=0;

	char buffer[MAX];

	fseek(fin,0,SEEK_END);
	t=ftell(fin)-1;
	fseek(fin,0,SEEK_SET);
	fread(buffer,1,MAX,fin);

	while(p<t){
		while((buffer[ptr]<'A'||('Z'<buffer[ptr]&&buffer[ptr]<'a')||'z'<buffer[ptr])&&p<=t){
			p++;
			if(++ptr>=MAX){
				fread(buffer,1,MAX,fin);
				ptr=0;
			}
		}
		while((('A'<=buffer[ptr]&&buffer[ptr]<='Z')||('a'<=buffer[ptr]&&buffer[ptr]<='z'))&&p<=t){
			cc++,p++;
			if(++ptr>=MAX){
				fread(buffer,1,MAX,fin);
				ptr=0;
			}
		}
		nc++;
	}
	if(nc!=0){
		fprintf(fout,"%u",cc/nc);
	}else{
		fprintf(fout,"%u",0);
	}
	fclose(fin);
	fclose(fout);
}