#include <iostream>
#include <fstream>

using namespace std;

const int INF = 1000000000;

int main(){
	int n;
	static int DP[3][40];
	int p[40], t[40];
	ifstream fin("B.in");
	while(fin >> n, n){
		for(int i=0;i<3;i++)
			for(int j=0;j<n;j++) DP[i][j] = INF;
		fin >> p[0] >> t[0];
		if(t[0] >= p[0]) DP[0][0] = p[0];
		for(int i=1;i<n;i++){
			fin >> p[i] >> t[i];
			for(int j=0;j<3;j++){
				if(DP[j][i-1] == INF) continue;
				if(t[i]-t[i-1] >= p[i]+(j+2)*p[i-1])
					DP[0][i] = min(DP[0][i], DP[j][i-1]+p[i]+p[i-1]);
				if(j!=2 && t[i]-t[i-1] >= (j+2)*abs(p[i]-p[i-1]))
					DP[j+1][i] = min(DP[j+1][i], DP[j][i-1]+abs(p[i]-p[i-1]));
			}
		}
		int res = INF;
		for(int i=0;i<3;i++)
			res = min(res, DP[i][n-1]+p[n-1]);
		if(res < INF) { cout << "OK " << res << endl; }
		else {
			res = 1;
			for(int i=0;i<n;i++)
				for(int j=0;j<3;j++)
					if(DP[j][i] < INF) res = i+2;
			cout << "NG " << res << endl;
		}
	}
}