#include <bits/stdc++.h>   using namespace std;   int main() {     int a;     cin >> a;     string s;     cin >> s;     int x = 0;     for (int i = 0; i < a - 1; i++) {       if (s[i] > s[i + 1]) {         cout <<  YES  << endl;         cout << i + 1 <<     << i + 2;         return 0;       }     }     cout <<  NO ;   }   