#include<iostream>
#include<vector>
#include<string>
#include<queue>
#include<sstream>
#include <cstring>
#include <algorithm>


#define REP(i,x) for(int i=0 ; i<(int)(x) ; i++)
#define LL long long
#define ALL(x) (x).begin(),(x).end()

using namespace std;

struct Stamp{
	int h,w;
	Stamp(){}
};

int N;
vector<Stamp> stamp;
vector<string> field;
int memo[1<<16];

int ctoi(char c){
	if(c=='R')return 0;
	if(c=='G')return 1;
	if(c=='B')return 2;
	return 3;
}

bool isValid(int x,int y){
	return x>=0 && y>=0 && x<4 && y<4;
}

int rec(int bit){
	char tmp[4][4];
	if(bit==((1<<16)-1))return 0;
	if(memo[bit]!=-1)return memo[bit];
	//cout << bit << endl;
	REP(y,4){
		REP(x,4){
			if((bit>>(y*4+x))&1)tmp[y][x] = 'W';
			else tmp[y][x] = field[y][x];
			//cout << tmp[y][x];
		}
		//cout << endl;
	}
	//cout << endl;
	int res = 1<<30;
	REP(i,N){
		int h = stamp[i].h;
		int w = stamp[i].w;
		for(int y=1-h ; y<4 ; y++){
			for(int x=1-w ; x<4 ; x++){
				int check[4] = {0};
				int nbit = bit;
				for(int cy=y ; cy<y+h ; cy++){
					for(int cx=x ; cx<x+w ; cx++){
						if(isValid(cx,cy)){
							nbit |= (1<<(cy*4+cx));
							check[ctoi(tmp[cy][cx])]=1;
						}
					}
				}
				int ok = check[0]+check[1]+check[2];
				if(ok==1){
					int t = rec(nbit);
					res = min(res,t);
					//if(bit==0)cout << nbit << " " << t << endl;
				}
			}
		}
	}
	//if(res==0){
	//	REP(y,4){
	//		REP(x,4)cout << tmp[y][x];
	//		cout << endl;
	//	}
	//	cout << endl;
	//}
	return memo[bit] = res+1;

}

int main(){
	int aaa = 1;
	REP(i,7)aaa*=i+1;
	aaa *= (1<<7);
	cout << aaa << endl;
	while(cin>>N){
		stamp.clear();
		field.clear();
		memset(memo,-1,sizeof(memo));
		REP(i,N){
			Stamp s;
			cin>>s.h>>s.w;
			stamp.push_back(s);
		}
		REP(y,4){
			string s;
			cin>>s;
			field.push_back(s);
		}
		int bit = 0;
		cout << rec(bit) << endl;
	}
	return 0;
}