Fibonacci Words

#include <bits/stdc++.h>
#define ll long long
#define ull unsigned long long int
#define ld long double
#define pb push_back
#define p_b pop_back
#define si stack<int>
#define sll stack<ll>
#define sc stack<char>
#define vi vector<int>
#define vll vector<ll>
#define mii map<int, int>
#define msi map<string, int>
#define mci map<char, int>
#define qc queue<char>
#define qi queue<int>
#define qll queue<ll>
using namespace std;

string fib_st(string s, map<char, int> m){
    for(int i = 2; i < s.length(); i++){
        if((m[s[i-2]]+m[s[i-1]])%26 == m[s[i]]){
            return "YES";
        }
    }
    return "NO";
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    string s;
    cin >> s;
    map<char, int> m;
    for(int i = 65; i < 91; i++){
        m[(char)i] = i-65;
    }
    cout << fib_st(s, m);
    return 0;
}