#include <fstream>
#include <string.h>
using namespace std;

int main()
{
	ifstream in("text.in"); ofstream out("text.out");
	char cuv[1100000];
	int nrl = 0, nrc = 0, i;
	while (in>>cuv)
	{
		bool litere = false;
		for (i=0;i<strlen(cuv);i++)
			if ((cuv[i] >= 'A' && cuv[i] <= 'Z') || (cuv[i] >= 'a' && cuv[i] <= 'z'))
			{
				litere = true;
				nrl++;
			}
		if (litere)
		{
			nrc++;
			for (i=1;i<strlen(cuv)-1;i++)
				if ((cuv[i] < 'A' || cuv[i] > 'Z') && (cuv[i] < 'a' || cuv[i] > 'z'))
					nrc++;
		}
	}
	out<<nrl/nrc;
	return 0;
}