/*
ID: espr1t
TASK: 
KEYWORDS: 
*/

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>
#include <string>

using namespace std;
FILE *in; FILE *out;

const int MAX = 100004;
const int TREE = 262144;
const long long INF = 1000000000000000001LL;

struct Building {
    int parent, area, weight, strength;
};

int n;
Building a[MAX];
vector <int> v[MAX];
long long area[MAX], tree[TREE];
int firstIndex[MAX], lastIndex[MAX], nextIndex = 0;


void update(int idx, long long val) {
    idx += (TREE >> 1);
    while (idx > 0) {
        tree[idx] += val;
        idx >>= 1;
    }
}

long long query(int idx1, int idx2) {
    if (idx1 > idx2)
        return 0;
    idx1 += (TREE >> 1), idx2 += (TREE >> 1);
    if (idx1 == idx2)
        return tree[idx1];
    long long ret = 0;
    ret += tree[idx1]; bool flag1 = !(idx1 & 1); idx1 >>= 1;
    ret += tree[idx2]; bool flag2 =  (idx2 & 1); idx2 >>= 1;
    while (idx1 != idx2) {
        if (flag1) ret += tree[(idx1 << 1) | 1]; flag1 = !(idx1 & 1); idx1 >>= 1;
        if (flag2) ret += tree[(idx2 << 1) | 0]; flag2 =  (idx2 & 1); idx2 >>= 1;
    }
    return ret;
}

void buildTree(int node) {
    firstIndex[node] = nextIndex++;
    for (int i = 0; i < (int)v[node].size(); i++) {
        buildTree(v[node][i]);
    }
    lastIndex[node] = nextIndex - 1;
}

bool simulate(int turns) {
    area[0] = INF;
    for (int i = 1; i <= n; i++)
        area[i] = a[i].area;
    memset(tree, 0, sizeof(tree));

    for (int i = 1; i <= turns; i++) {
        area[a[i].parent] -= a[i].area;
        if (area[a[i].parent] < 0)
            return false;
        update(firstIndex[i], a[i].weight);
    }
    for (int i = 1; i <= n; i++) {
        int idx1 = firstIndex[i] + 1, idx2 = lastIndex[i];
        if (query(idx1, idx2) > a[i].strength)
            return false;
    }
    return true;
}

void solve() {
    for (int i = 1; i <= n; i++)
        v[a[i].parent].push_back(i);
    buildTree(0);
    
    int ans = n + 1;
    int left = 1, right = n;
    while (left <= right) {
        int mid = (left + right) / 2;
        if (simulate(mid))
            left = mid + 1;
        else
            right = mid - 1, ans = mid;
    }

    if (ans > n) {
        fprintf(out, "OK\n");
        return;
    }
    
    area[0] = INF;
    for (int i = 1; i <= n; i++)
        area[i] = a[i].area;
    
    for (int i = 1; i <= ans; i++) {
        area[a[i].parent] -= a[i].area;
    }

    if (area[a[ans].parent] < 0) {
        fprintf(out, "IMPOSSIBLE %d\n", ans);
    } else {
        fprintf(out, "COLLAPSE %d\n", ans);
    }
}

int main(void) {
	in = stdin; out = stdout;
	in = fopen("building.in", "rt"); out = fopen("building.out", "wt");
	
	fscanf(in, "%d", &n);
	for (int i = 1; i <= n; i++)
	    fscanf(in, "%d %d %d %d", &a[i].parent, &a[i].area, &a[i].weight, &a[i].strength);
	
	solve();
	
	return 0;
}