A. Team Olympiad

#include <bits/stdc++.h>

using namespace std ;
#define sz(s) int(s.size())
#define all(s) s.begin() , s.end()
#define getline(s) getline(cin >> ws, s)
#define cin(v) for (auto& i : v) cin >> i ;
#define cout(v) for (auto& i : v) cout << i << " "
#define pb(x) push_back(x)
#define ll long long
#define ull unsigned long long
#define Mod 1'000'000'007
#define INF 2'000'000'000
#define Num_of_Digits(n) ((int)log10(n)+1)
#define fixed(n) fixed << setprecision(n)
#define imin INT_MIN
#define imax INT_MAX
#define Time cerr << "Time Taken: " << (float)clock() / CLOCKS_PER_SEC << " Secs" << "\n" ;

void ABDEL3AL () {
    ios_base::sync_with_stdio(false); cin.tie(nullptr) , cout.tie(nullptr) ;
#ifndef ONLINE_JUDGE
    freopen("input.txt" , "r" , stdin) , freopen("output.txt" , "w" , stdout) ;
#endif
    Time
}

int main() {
    ABDEL3AL() ;
    int n ; cin >> n ;
    int num = 0 ;
    vector < int > v(n) ; cin(v) ;
    vector < int > v1 , v2 , v3 ;
    set < int > st ;
    for (int i = 0; i < n; i++) {
        if (v[i] == 1) v1.push_back(i) ;
        else if (v[i] == 2) v2.push_back(i) ;
        else v3.push_back(i) ;
    }
    for (int i = 0; i < n; i++) {
        st.insert({v1[i] , v2[i] , v3[i]}) ;
        if (sz(st) % 3 == 0) num++ ;
        else break ;
    }
    if (num > 0) {
    cout << num << "\n" ;
    for (int i = 0; i < num; i++) cout << v1[i] << " " << v2[i] << " " << v3[i] << "\n" ;
    } else {
        cout << num ;
    }


    return 0;
}