#include <cstdio>
#include <cstring>
using namespace std;

char q[300000];

int main()
{


    freopen("text.in","r",stdin);
    freopen("text.out","w",stdout);

    int n, i, s, t, d, k;
    s = d = 0;

    while( scanf("%s",q) != EOF ){
        n = strlen(q);
        for( i = 0; i < n; ++i ){
            if( q[i] >= 'a' && q[i] <= 'z' || q[i] >= 'A' && q[i] <= 'Z' ) s++;
        }
        d++;
    }

    //printf("%d %d\n",s,d);
    printf("%d",s/d);

    return 0;
}