#include <bits/stdc++.h>   using namespace std;   int main() {     ios_base::sync_with_stdio(false);     cin.tie(nullptr);     long long n;     cin >> n;     string s;     cin >> s;     for (long long i = 0; i < n - 1; i++) {       if (s[i] > s[i + 1]) {         cout <<  YES  << endl;         cout << i + 1 <<     << i + 2 << endl;         return 0;       }     }     cout <<  NO  << endl;     return 0;   }   