day 1, D 100 (0.974 max)

#include <bits/stdc++.h>
// tiom4eg's precompiler options
// POGGERS POGGERS POGGERS POGGERS POGGERS POGGERS POGGERS
// IO settings
#define fastIO ios_base::sync_with_stdio(false); cin.tie(0)
// Quick types
#define ll long long
#define ld long double
#define ull unsigned long long
#define pii pair <int, int>
#define vi vector <int>
#define mi vector <vector <int>>
// Quick functions
#define endl "\n"
#define F first
#define S second
#define all(a) a.begin(), a.end()
#define sz(a) (int)(a.size())
#define pb push_back
#define mp make_pair
// Quick fors
#define FOR(i, a, b) for (int i = a; i < b; ++i)
#define FORS(i, a, b, c) for (int i = a; i < b; i += c)
#define RFOR(i, a, b) for (int i = a; i >= b; --i)
#define EACH(e, a) for (auto& e : a)
// Pragmas
#ifndef TIOM4EG
#pragma GCC optimize("O2") // let the chaos begin!
//#pragma GCC target("avx,avx2,bmi,bmi2,popcnt,lzcnt,tune=native")
//#pragma GCC comment(linker, "/stack:200000000")
#endif
// PBDS
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ordered_set tree <int, null_type, less <int>, rb_tree_tag, tree_order_statistics_node_update>
#define ook order_of_key
#define fbo find_by_order
using namespace __gnu_pbds;
// POGGERS POGGERS POGGERS POGGERS POGGERS POGGERS POGGERS
using namespace std;
mt19937 rng(chrono::duration_cast<chrono::milliseconds>(chrono::system_clock::now().time_since_epoch()).count());
//#define int long long
const int INF = 1e9 + 7, MD = 998244353, MAX = 300005, R = 1 << 19, MOD1 = 1e9 + 7, MOD2 = 1e9 + 9, MOD12 = MOD1 * MOD1, MOD22 = MOD2 * MOD2, LG = 20, B1 = 103, B2 = 107, S = 10008;
const ll INFLL = 1e18 + 7;

int nx[MAX][LG], lv[MAX][LG];
vector <pii> cur, o[LG];

signed main() {
    fastIO;
    int n, m, k, b = 0, g = 0, r = 0; cin >> n >> m >> k, --k;
    cur.reserve(n);
    pair <int, char> t[n];
    FOR(i, 0, n) {
        cin >> t[i].F >> t[i].S, --t[i].F;
        if (t[i].S == 'B') ++b;
        else if (t[i].S == 'G') ++g;
        else ++r;
    }
    FOR(i, 0, n) nx[i][0] = t[i].F;
    FOR(i, 1, LG) FOR(j, 0, n) nx[j][i] = nx[nx[j][i - 1]][i - 1];
    FOR(i, 0, n) {
        if (t[i].S == 'B') lv[i][0] = 0;
        else if (t[i].S == 'G') lv[i][0] = b;
        else lv[i][0] = b + g;
        o[0].pb({lv[i][0], i});
    }
    sort(all(o[0]));
    FOR(i, 1, LG) {
        int p = 0;
        FOR(j, 1, n) if (o[i - 1][p].F < o[i - 1][j].F) {
            FOR(k, p, j) cur.pb({lv[nx[o[i - 1][k].S][i - 1]][i - 1], o[i - 1][k].S});
            sort(all(cur));
            lv[cur[0].S][i] = p, o[i].pb({p, cur[0].S});
            FOR(k, 1, j - p) lv[cur[k].S][i] = (cur[k].F == cur[k - 1].F ? lv[cur[k - 1].S][i] : p + k), o[i].pb({lv[cur[k].S][i], cur[k].S});
            cur.clear(), p = j;
        }
        vector <pii> cur;
        FOR(k, p, n) cur.pb({lv[nx[o[i - 1][k].S][i - 1]][i - 1], o[i - 1][k].S});
        sort(all(cur));
        lv[cur[0].S][i] = p, o[i].pb({p, cur[0].S});
        FOR(k, 1, n - p) lv[cur[k].S][i] = (cur[k].F == cur[k - 1].F ? lv[cur[k - 1].S][i] : p + k), o[i].pb({lv[cur[k].S][i], cur[k].S});
        cur.clear();
    }
    int st = o[LG - 1][n - 1].S;
    FOR(i, 0, n) if (o[LG - 1][i].F > k) {
        st = o[LG - 1][i - 1].S;
        break;
    }
    FOR(i, 0, m) {
        cout << t[st].S;
        st = t[st].F;
    }
}