#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;


int main() {
    string s;
    cin >> s;


    int res = 0;
    for(int i = 0; i < s.length(); i++) {
        if(s[i] == 'Y') {
            for(int j = i; j < s.length(); j += i + 1) {
                if(s[j] == 'N') {
                    s[j] = 'Y';
                }
                else {
                    s[j] = 'N';
                }
            }
            res++;
        }
    }

    cout << res << endl;
    return 0;
}

/// YNYYYNYNY