Book writing

#include <bits/stdc++.h>

using namespace std;
typedef long long ll;


ll power(ll n, ll m) {
    
    if ( n == 0) return 1 % m;
    if (n == 1) return 3 % m;
    
    if (n % 2 == 0) {
        ll lol = power(n/2, m);
        return ((lol % m) * (lol % m)) % m;
        
    }
    ll lol = power((n-1) / 2, m);
    return (3 * ((lol % m) * (lol % m)) % m)%m;
}

int main() {
    ios_base::sync_with_stdio(0);

    ll n, m;
    cin >> n >> m;
    
    cout << (power(n-1, m)) << endl;
    
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED

Test 15

Verdict: ACCEPTED