#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <climits>
#include <cfloat>
#include <ctime>
#include <cassert>
#include <map>
#include <utility>
#include <set>
#include <iostream>
#include <memory>
#include <string>
#include <vector>
#include <algorithm>
#include <functional>
#include <sstream>
#include <complex>
#include <stack>
#include <queue>
#include <numeric>
#include <list>
#include <iomanip>
#include <fstream>
   
using namespace std;
   

#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define foreach(it, c) for (__typeof__((c).begin()) it=(c).begin(); it != (c).end(); ++it)
#define rforeach(it, c) for (__typeof__((c).rbegin()) it=(c).rbegin(); it != (c).rend(); ++it)
#define all(c) (c).begin(), (c).end()
#define rall(c) (c).rbegin(), (c).rend()
#define CL(arr, val) memset(arr, val, sizeof(arr))
#define COPY(dest, src) memcpy(dest, src, sizeof(dest))
#define ten(n) ((long long)(1e##n))
#define bin(n) (1LL << (n))

template <class T> void max_swap(T& a, const T& b) { a = max(a, b); }
template <class T> void min_swap(T& a, const T& b) { a = min(a, b); }

template <class T> void uniq(vector<T>& c) { sort(c.begin(), c.end()); c.erase(unique(c.begin(), c.end()), c.end()); }

template <class T> string to_s(const T& a) { ostringstream os; os << a; return os.str(); }
template <class T> T to_T(const string& s) { istringstream is(s); T res; is >> res; return res; }
  
template <class T, class U> ostream& operator<<(ostream& os, pair<T, U>& p) { os << "( " << p.first << ", " << p.second << " )"; return os; }
  
template <class T> void print(T a, int n, const string& deli = " ", int br = 1) { for (int i = 0; i < n; ++i) { cout << a[i]; if (i + 1 != n) cout << deli; } while (br--) cout << endl; }
template <class T> void print(const T& c, const string& deli = " ", int br = 1) { foreach (it, c) { cout << *it; if (++it != c.end()) cout << deli;--it; } while (br--) cout << endl; }
template <class T> void print2d(T a, int w, int h, int width = -1, int br = 1) { for (int i = 0; i < h; ++i) { for (int j = 0; j < w; ++j) {    if (width != -1) cout.width(width); cout << a[i][j] << ' '; } cout << endl; } while (br--) cout << endl; }
   
template <class T> void input(T& a, int n) { for (int i = 0; i < n; ++i) cin >> a[i]; }
template <class T> void input(T* a, int n) { for (int i = 0; i < n; ++i) cin >> a[i]; }

void fast_io() { cin.tie(0); ios::sync_with_stdio(false); }
#define trace(x) (cout << #x << ": " << (x) << endl)

bool valid(int x, int y, int w, int h) { return 0 <= x && x < w && 0 <= y && y < h; }


typedef long long ll;
typedef pair<int, int> pint;

const int dx[] = { 0, 1, 0, -1 };
const int dy[] = { 1, 0, -1, 0 };
  
const double PI = acos(-1.0);
const int mod = ten(9) + 7;



int main()
{
    fast_io();

    int n;
    while (cin >> n, n)
    {
        int p[55], t[55];
        rep(i, n)
            cin >> p[i] >> t[i];
        p[n] = 0;
        t[n] = ten(5);

        const int INF = ten(7);
        int dp[55][4];
        rep(i, n + 1) rep(j, 4)
            dp[i][j] = INF;
        if (p[0] <= t[0])
            dp[0][0] = p[0];
        int captured = 0;
        rep(i, n)
        {
            rep(j, 3)
            {
                if (dp[i][j] == INF)
                    continue;

                captured = i + 1;
                int nj = j + 1;


                // direct
                {
                    int nt = t[i] + (nj + 1) * abs(p[i + 1] - p[i]);
                    int nc = dp[i][j] + abs(p[i + 1] - p[i]);
                    if (nt <= t[i + 1])
                        min_swap(dp[i + 1][nj], nc);
                }

                // house
                {
                    int nt = t[i] + (nj + 1) * p[i] + p[i + 1];
                    int nc = dp[i][j] + p[i] + p[i + 1];
                    if (nt <= t[i + 1])
                        min_swap(dp[i + 1][0], nc);
                }
            }
        }

        int res = dp[n][0];
        if (res != INF)
            cout << "OK " << res << endl;
        else
            cout << "NG " << captured + 1 << endl;
    }
}

Measured memory_bytes: 1196