string runMatrix(string stringA, string stringB, int positionA, int positionB){
	// Local variables
	// return string
	string ret;
	// copy both positions to be able to change them saving the previous result
	int posA = positionA-1;
	int posB = positionB-1;

	// body
	// while the positions are in range
	while(posA >= 0 && posB >= 0){
		// if the chars match decrement both positions and add the char to the ret string
		if(stringA[posA] == stringB[posB]){
			if(posA == 0 && posB == 0){ //mandar para o bloco diagonal
				//if(){ ver quem é que está a enviar e quem está a receber
					MPI_Cart_rank(cart_comm, destinationCoords, &destinationId1);
					MPI_Send(dependencyListSide, dependencies, MPI_INT, destinationId1, destinationId1, MPI_COMM_WORLD);
				//}else{
					MPI_Cart_rank(cart_comm, sourceCoords, &sourceId);
					MPI_Recv(dependencyList, dependencies, MPI_INT, sourceId, id, MPI_COMM_WORLD, &status);
				//}
			}else{
				if(posA == 0){ //mandar para o bloco da esquerda

				}else if(posB == 0){ //mandar para o bloco de cima

				}else{
					ret = stringA[posA] + ret;
					posA--;
					posB--;
				}
			}
		} else{
			if(posA==0 && posB==0)
				break;
		}
	} // ends while loop
	// return ret string
	return ret;
}