Language: C++

#include<iostream>
#include<vector>
#include<algorithm>
#include <iterator>
#include<queue>
#include <string>
#include <numeric>
#include<stack>
using namespace std;
#define rep(i,n) for(int i=0;i<(n);i++)
#define all(v) v.begin(),v.end()

struct Node{
	int id;
	int alpha;
	vector<int> ToCole;
};
vector<char> AlphaCole;
vector<vector<Node>> NodeColes(2);
int GetAns(vector<vector<int>> IsSelected,vector<vector<int>>& memo, int p1, int p2, int score){
	if (score > 10000)return -1;
	IsSelected[p1][p2] = score;

	Node Node1 = NodeColes[0][p1];
	Node Node2 = NodeColes[1][p2];
	if (memo[p1][p2] <= score){
		int size1 = Node1.ToCole.size();
		int size2 = Node2.ToCole.size();
		if (Node1.alpha == Node2.alpha){
			score++;
			memo[p1][p2] = score;
			
			for (auto i:Node1.ToCole){
				for(auto j:Node2.ToCole){
					if (IsSelected[i][j] != -1){
						if (IsSelected[i][j] != score){
							return -1;
						}
						else{
							continue;
						}
					}
					if (GetAns(IsSelected, memo, i, j, score) == -1){ return -1; }
				}
			}
		}
		else{
			if (memo[p1][p2] == score)return 0;
			memo[p1][p2] = score;
			for (auto i : Node1.ToCole){
				for (auto j : Node2.ToCole){
					if (IsSelected[i][j] != -1){
						if (IsSelected[i][j] != score){
							return -1;
						}
						else{
							continue;
						}
					}
					if (GetAns(IsSelected, memo, i, j, score) == -1){ return -1; }
				}
			}
			for (auto j : Node2.ToCole){
				if (IsSelected[i][j] != -1){
					if (IsSelected[i][j] != score){
						return -1;
					}
					else{
						continue;
					}
				}
				if (GetAns(IsSelected, memo, p1, j, score) == -1){ return -1; }
			}
			for (auto i : Node1.ToCole){
				if (IsSelected[i][j] != -1){
					if (IsSelected[i][j] != score){
						return -1;
					}
					else{
						continue;
					}
				}
				if (GetAns(IsSelected, memo, i, p2, score) == -1){ return -1; }
			}
		}
	}
	else{
		return 0;
	}
	return 0;
}
int main(){
	int boardNums[2];
	rep(i, 2){
		int n, m;
		cin >> boardNums[i] >> m;
		rep(j, boardNums[i]){
			char c;
			cin >> c;
			int aalpha;
			if (find(AlphaCole.begin(), AlphaCole.end(), c) == AlphaCole.end()){
				AlphaCole.push_back(c);			
			}
			else{
			}
			aalpha = find(AlphaCole.begin(), AlphaCole.end(), c) - AlphaCole.begin();
			NodeColes[i].push_back({ j, aalpha });
		}
		rep(j, m){
			int a, b;
			cin >> a >> b;
			NodeColes[i][a - 1].ToCole.push_back(b - 1);
		}
	}
	vector<vector<int>>memo(boardNums[0], vector<int>(boardNums[1],-1));
	rep(i, boardNums[0]){
		rep(j, boardNums[1]){
			vector<vector<int>> IsSelected(boardNums[0], vector<int>(boardNums[1], -1));
			if (GetAns(IsSelected,memo, i, j, 0) == -1){
				cout << -1 << endl;
				return 0;
			}
		}
	}
	vector<int>maxCol;
	rep(i, boardNums[0]){
		maxCol.push_back(*max_element(memo[i].begin(), memo[i].end()));
	}
	cout << *max_element(maxCol.begin(), maxCol.end())<<endl;
	return 0;
}

Compiler output:
a.cc: In function 'int GetAns(std::vector<std::vector<int> >, std::vector<std::vector<int> >&, int, int, int)':
a.cc:64:48: error: 'i' was not declared in this scope
   64 |                                 if (IsSelected[i][j] != -1){
      |                                                ^
a.cc:75:51: error: 'j' was not declared in this scope
   75 |                                 if (IsSelected[i][j] != -1){
      |                                                   ^